Image processing apparatus and method in which a discrimination standard is set and displayed

ABSTRACT

An image processing apparatus includes an input device for image data, a discriminating device for discriminating a type of an image represented by the image data, a setting device for setting a discrimination standard of the discriminating device, and a display for displaying a condition of the setting device.

This application is a division of application Ser. No. 08/481,825, filedJun. 7, 1995, now U.S. Pat. No. 5,550,638 which is a continuation ofapplication Ser. No. 08/021,853, filed Feb. 24, 1993, now abandoned, andwhich in turn, is a division of application Ser. No. 07/519,448, filedMay 4, 1990, which issued as U.S. Pat. No. 5,239,383 on Aug. 24, 1993.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing apparatus whichexecutes various processing operations of an input image to performimage edit operations.

2. Related Background Art

In a conventional digital copying machine, an original is illuminatedwith a halogen lamp or the like, and light reflected by the original iscolor-separated into, e.g., R (red), G (green), and B (blue) by anoptical means such as an optical filter or a prism. The R, G, and Bsignals are photoelectrically converted to electrical signals using acharge-coupled device such as a CCD. The electrical signals are thenconverted into digital signals, and the digital signals are subjected topredetermined processing. Thereafter, an image is formed using arecording apparatus such as a laser beam printer, a liquid crystalprinter, a thermal printer, an ink-jet printer, or the like.

In a digital copying machine of this type, requirements for outputtingsmooth images, and outputting sharp characters and lines have beendemanded, and extensive studies have been made to meet suchrequirements.

However, in an area gradation system in which gradation of an image isassured by a dot area, gradation of an output image conflicts with aresolution level, and different processing operations must be performedfor an image portion and a character portion. Although many systems havebeen introduced so far, complex software processing must be executed inmost of them. Some real-time processing systems become very expensivedue to their circuit scales, and are not suitable for commercialproducts.

SUMMARY OF THE INVENTION

It is an object of the present invention to eliminate the conventionaldrawbacks.

It is another object of the present invention to provide an imageprocessing apparatus which can reliably discriminate a character areafrom an image area.

In order to achieve the above objects, according to the presentinvention, there is provided an image processing apparatus comprisingmeans for emphasizing a high-frequency component of an input imagesignal, and means for discriminating a dot area of an image based on theimage signal whose high-frequency component is emphasized by theemphasizing means.

Furthermore, there is provided an image processing apparatus comprisingmeans for emphasizing a high-frequency component of an input imagesignal, and means for discriminating an outline portion of an image onthe basis of the image signal whose high-frequency component isemphasized by the emphasizing means.

Moreover, there is provided an image processing apparatus comprisingmeans for emphasizing a high-frequency component of an input imagesignal, and means for discriminating a halftone area of an image on thebasis of the image signal whose high-frequency component is emphasizedby the emphasizing means.

It is still another object of the present invention to provide an imageprocessing apparatus which can reliably perform image area separation ofa color image.

In order to achieve the above object, according to the presentinvention, there is provided an image processing apparatus comprisingmeans for inputting a plurality of color component signals of asubtractive color system, means for detecting a minimum value signalfrom the color component signals input by the input means, means foremphasizing a high-frequency component of the minimum value signaldetected by the detection means, and means for discriminating a featureof an image in accordance with the minimum value signal whosehigh-frequency component is emphasized by the emphasizing means.

It is still another object of the present invention to provide an imageprocessing apparatus which can precisely reproduce an original image.

In order to achieve the above object, according to the presentinvention, there is provided a copying apparatus comprising conversionmeans for scanning an original to convert an original image into aplurality of color component signals, means for detecting a minimumvalue signal from the color component signals converted by theconversion means, means for emphasizing a high-frequency component ofthe minimum value signal detected by the detection means, means fordiscriminating a feature of an image in accordance with the minimumvalue signal whose high-frequency component is emphasized by theemphasizing means, and means for reproducing the original image inaccordance with the discrimination result by the discrimination means.

It is still another object of the present invention to provide an imageprocessing apparatus which can perform image area separation in realtime.

It is still another object of the present invention to provide a simple,inexpensive image processing apparatus.

Other objects of the present invention will be apparent from thefollowing description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an overall image processing apparatusaccording to an embodiment of the present invention:

FIG. 2, including FIGS. 2A, 2B, and 2C, is a block diagram of an imageprocessing circuit according to the embodiment of the present invention;

FIGS. 3A and 3B are respectively a schematic view and a timing chartshowing color read sensors and drive pulses;

FIGS. 4A and 4B are respectively a circuit diagram and a timing chart ofan ODRV 118a and an EDRV 119a;

FIGS. 5A and 5B are respectively a circuit diagram and a schematic viewfor explaining a black correction operation;

FIGS. 6A to 6D are respectively a circuit diagram and schematic viewsfor explaining shading correction;

FIG. 7 is a block diagram of a color conversion section;

FIG. 8, including FIGS. 8A and 8B, is a block diagram of a colordetection unit;

FIG. 9 is a block diagram of a color conversion circuit;

FIG. 10 is a view showing an example of color conversion;

FIGS. 11A and 11B are views for explaining logarithmic conversion;

FIGS. 12A and 12B are respectively a circuit diagram and a table forexplaining a color correction circuit;

FIG. 13 shows unnecessary transmission regions of a filter;

FIG. 14 shows unnecessary absorption components of a filter;

FIGS. 15A to 15C are respectively circuit diagrams and a view forexplaining a character/image area separation circuit;

FIGS. 16A to 16E are views for explaining the principle of outlineregeneration;

FIGS. 17A to 17N are views for explaining the principle of outlineregeneration;

FIG. 18 is a circuit diagram of an outline regeneration circuit;

FIG. 19 is a circuit diagram of the outline regeneration circuit;

FIG. 20 is a timing chart of signals EN1 and EN2;

FIG. 21, including FIGS. 21A and 21B, is a block diagram of acharacter/image correction unit;

FIG. 22A-1 illustrates a character "N," a portion of which is to besubject to addition/subtraction processing;

FIGS. 22A to 22D are views for explaining addition/subtractionprocessing performed on a portion of character "N" shown in FIG. 22A-1;

FIG. 23 is a circuit diagram of a switching signal generation circuit;

FIG. 24 is a color residual removal processing circuit;

FIGS. 25A to 25Q are views for explaining color residual removalprocessing, addition/subtraction processing, and the like;

FIG. 26 is a view showing edge emphasis processing;

FIG. 27 is a view showing smoothing processing;

FIGS. 28A to 28C are respectively a circuit diagram and views forexplaining image process and modulation using binary signals;

FIGS. 29A to 29D are views showing character/image synthesizingprocessing;

FIG. 30 is a block diagram of an image process and edit circuit;

FIGS. 31A to 31C are views showing texture processing;

FIG. 32 is a circuit diagram of a texture processing circuit;

FIG. 33 is a circuit diagram of a zoom, mosaic, taper processing unit;

FIG. 34 is a circuit diagram of a mosaic processing unit;

FIGS. 35A to 35F are views and a circuit diagram for explaining mosaicprocessing, and the like;

FIG. 36 is a circuit diagram of a line memory address control unit;

FIGS. 37A to 37N are a circuit diagram, timing charts, and explanatoryviews of a mask bit memory, and the like;

FIG. 38 is a view showing addresses;

FIG. 39 is a view showing an example of a mask;

FIG. 40 is a circuit diagram of an address counter;

FIG. 41 is a timing chart in enlargement and reduction states;

FIGS. 42A to 42C are views showing an example of enlargement andreduction;

FIGS. 43A to 43C are circuit diagrams and a schematic view of abinarization circuit;

FIG. 44 is a timing chart of an address counter;

FIGS. 45A and 45A' are charts showing an example of bit map;

FIGS. 46A to 46D are views showing an example of character/imagesynthesizing processing;

FIG. 47 is a circuit diagram of a switch circuit;

FIGS. 48A to 48C show an example of a non-linear mask;

FIGS. 49A to 49F are explanatory views and a circuit diagram of an areasignal generation circuit;

FIG. 50 shows area designation by a digitizer;

FIG. 51 is a circuit diagram of an interface with an external apparatus;

FIG. 52 shows a truth table of a selector;

FIGS. 53A and 53B show examples of rectangular and non-rectangularareas;

FIG. 54 shows an outer appearance of an operation unit;

FIG. 55, including FIGS. 55A, 55B, and 55C, is a chart for explaining acolor conversion sequence;

FIG. 56, including FIGS. 56A, 56B, 56C, and 56D, is a chart forexplaining a trimming area designation sequence;

FIG. 57 is a view for explaining the trimming area designation sequence;

FIG. 58 is a flow chart showing a circular area designation algorithm;

FIG. 59 is a flow chart showing an elliptical and R rectangular areadesignation algorithm;

FIG. 60, including FIGS. 60A, 60B, and 60C, is a chart for explaining acharacter synthesizing sequence;

FIG. 61, including FIGS. 61A, 61B, 61C, 61D, 61E, and 61F, is a chartfor explaining the character synthesizing sequence;

FIG. 62 is a chart for explaining the character synthesizing sequence;

FIGS. 63A, including FIGS. 63A-1 and 63A-2, and 63B-1 and 63B-2 arecharts for explaining texture processing;

FIGS. 64A and 64B are charts for explaining mosaic processing;

FIG. 65, including FIGS. 65A, 65B, 65C, and 65D, is a chart forexplaining an * mode sequence;

FIG. 66, including FIGS. 66A, 66B, and 66C is a chart for explaining aprogram memory operation sequence;

FIG. 67, including FIGS. 67A and 67B, is a chart for explaining theprogram memory operation sequence;

FIGS. 68A and 68B are charts for explaining the program memory operationsequence;

FIG. 69 is a flow chart showing a program memory registration algorithm;

FIG. 70 is a flow chart showing an algorithm of an operation after aprogram memory is called;

FIG. 71 shows a format of a recording table;

FIGS. 72A to 72D are views showing image process and edit processing;

FIGS. 73A to 73C are respectively a partial circuit diagram and timingcharts of a driver of a color laser beam printer;

FIGS. 74A and 74B are graphs showing contents of a gradation correctiontable; and

FIG. 75 is a perspective view showing an outer appearance of a laserbeam printer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail below with referenceto the accompanying drawings.

FIG. 1 schematically shows an internal arrangement of a digital colorimage processing system according to the present invention. The systemof this embodiment comprises a digital color image reading apparatus (tobe referred to as a color reader hereinafter) 1 in an upper portion, anda digital color image print apparatus (to be referred to as a colorprinter hereinafter) 2 in a lower portion, as shown in FIG. 1. The colorreader 1 reads color image information of an original in units of colorsby a color separation means and a photoelectric transducer such as a CCD(to be described later), and converts the read information into anelectrical digital image signal. The color printer 2 comprises anelectrophotograpic laser beam color printer which reproduces colorimages in units of colors in accordance with the digital image siganl,and transfers the reproduced images onto a recording sheet in a digitaldot format a plurality of times, thereby recording an image.

The color reader 1 will be briefly described below.

The color reader 1 includes a platen glass 4 on which an original 3 isto be placed, and a red lens array 5 for converging an optical imagereflected by an original which is exposure-scanned by a halogen exposurelamp 10, and inputting the focused image onto an equi-magnificationfull-color sensor 6. The components 5, 6, 7, and 10 exposure-scan theoriginal in a direction of an arrow A1 together with an originalscanning unit 11. Color separation image signals of one line read duringexposure scanning are amplified to predetermined voltages by a sensoroutput signal amplifier circuit 7, and the amplified signals are inputto a video processing unit 12 (to be described later) through a signalline 501. The input signals are then subjected to signal processing. Thevideo processing unit 12 and its signal processing will be described indetail later. The signal line 501 comprises a coaxial cable which canguarantee faithful signal transmission. A signal line 502 is used tosupply drive pulses to the equi-magnification full-color sensor 6. Allthe necessary drive pulses are generated by the video processing unit12. The color reader 1 also includes white and black plates 8 and 9 usedfor white and black level correction of image signals (to be describedlater). When the black and white plates 8 and 9 are irradiated withlight emitted from the halogen exposure lamp 10, signal levels ofpredetermined densities can be obtained. Thus, these plates are used forwhite and black level correction of video signals. The color reader 1includes a control unit 13 having a microcomputer. The control unit 13performs all the control operations of the color reader 1, e.g., displayand key input control of an operation panel 1000 through a bus 508,control of the video processing unit 12, detection of a position of theoriginal scanning unit 11 using position sensors S1 and S2 throughsignal lines 509 and 510, control of a stepping motor drive circuit forpulse-driving a stepping motor 14 or moving the original scanning unit11 through a signal line 503, ON/OFF control of the halogen exposurelamp 10 using an exposure lamp driver through a signal line 504, controlof a digitizer 16 and internal keys through a signal line 505, and thelike. In an original exposure-scanning mode, color image signals read bythe exposure scanning unit 11 described above are input to the videoprocessing unit 12 through the amplifier circuit 7 and the signal line501, and are subjected to various processing operations (to be describedlater). The processed signals are then sent to the color printer 2through an interface circuit 56.

The color printer 2 will be briefly described below. The printer 2includes a scanner 711. The scanner 711 comprises a laser output unitfor converting image signals from the color reader 1 into light signals,a polygonal mirror 712 of a polygon (e.g., an octahedron), a motor (notshown) for rotating the mirror 712, an f/θ lens (focusing lens) 713, andthe like. The color printer 2 includes a reflection mirror 714, and aphotosensitive drum 715. A laser beam emerging from the laser outputunit is reflected by the polygonal mirror 712, and linearly scans(raster-scans) the surface of the photosensitive drum 715 via the lens713 and the mirror 714, thereby forming a latent image corresponding toan original image.

The color printer 2 also includes an entire surface exposure lamp 718, acleaner unit 723 for recovering a non-transferred residual toner, and apretransfer charger 724. These members are arranged around thephotosensitive drum 715.

Furthermore, the color printer 2 includes a developing unit 726 fordeveloping an electrostatic latent image formed on the surface of thephotosensitive drum 715, developing sleeves 731Y, 731M, 731C, and 731Bkwhich are brought into direct contact with the photosensitive drum 715to perform developing, toner hoppers 730Y, 730M, 730C, and 730Bk forstoring supplementary toners, and a screw 732 for transferring adeveloping agent. These sleeves 731Y to 731Bk, the toner hoppers 730Y to730Bk, and the screw 732 constitute the developing unit 726. Thesemembers are arranged around a rotating shaft P of the developing unit.For example, when a yellow toner image is to be formed, yellow tonerdeveloping is performed at a position illustrated in FIG. 1. When amagenta toner image is to be formed, the developing unit 726 is rotatedabout the shaft P in FIG. 1, so that the developing sleeve 731M in amagenta developing unit is located at a position where it can be incontact with the photosensitive drum 715. Cyan and black images aredeveloped in the same manner as described above.

The color printer 2 includes a transfer drum 716 for transferring atoner image formed on the photosensitive drum 715 onto a paper sheet, anactuator plate 719 for detecting a moving position of the transfer drum716, a position sensor 720 which approaches the actuator plate 719 todetect that the transfer drum 716 is moved to a home position, atransfer drum cleaner 725, a sheet pressing roller 727, a discharger728, and a transfer charger 729. These members 719, 720, 725, 727, and729 are arranged around the transfer roller 726.

The color printer 2 also includes sheet cassettes 735 and 736 forstoring paper sheets (cut sheets), sheet feed rollers 737 and 738 forfeeding paper sheets from the cassettes 735 and 736, and timing rollers739, 740, and 741 for taking sheet feed and convey timings. A papersheet fed and conveyed via these rollers is guided to a sheet guide 749,and is wound around the transfer drum 716 while its leading end iscarried by a gripper (to be described later). Thus, an image formationprocess is started.

Moreover, the color printer includes a drum rotation motor 550 forsynchronously rotating the photosensitive drum 715 and the transfer drum716, a separation pawl 750 for separating a paper sheet from thetransfer drum 716 after the image formation process is completed, aconveyor belt 742 for conveying the separated paper sheet, and an imagefixing unit 743 for fixing a toner image on the paper sheet conveyed bythe conveyor belt 742. The image fixing unit 743 comprises a pair ofheat and press rollers 744 and 745.

An image processing circuit according to the present invention will bedescribed below with reference to FIG. 2 and subsequent drawings. Thiscircuit can be applied to a color image copying apparatus in which afull-color original is exposed with an illumination source such as ahalogen lamp or a fluorescent lamp (not shown), a reflected color imageis picked up by a color image sensor such as a CCD, and an obtainedanalog image signal is converted into a digital signal by an A/Dconverter or the like, the digital full-color image is processed, andthe processed signal is output to a thermal transfer color printer, anink-jet color printer, a laser beam color printer, or the like (notshown) to obtain a color image, or a color image output apparatus whichreceives a digital color image signal in advance from a computer,another color image reading apparatus, a color image transmissionapparatus, or the like, performs processing such as synthesizing, andoutputs the processed signal. This circuit can also be applied to a headfor causing film boiling by heat energy to inject ink droplets, and arecording system using this head. This technique is disclosed in U.S.Pat. Nos. 4,740,796 and 4,740,793.

In FIG. 2, an image reading unit A comprises staggered CCD line sensors500a, a shift register 501a, a sample/hold circuit 502a, an A/Dconverter 503a, a positional aberration correction circuit 504a, blackcorrection/white correction circuit 506a, a CCD driver 533a, a pulsegenerator 534a, and an oscillator 558a.

The image processing circuit includes a color conversion circuit B, aLOG conversion circuit C, a color correction circuit D, a line memory O,a character/image correction circuit E, a character synthesizing circuitF, a color balance circuit P, an image process and edit circuit G, anedge emphasis circuit H, a character/image area separation circuit I, anarea signal generation circuit J, a 400-dpi binary memory K, a 100-dpibinary memory L, an external apparatus interface M, a switch circuit N,a binarization circuit 532, a driver R such as a laser driver for alaser beam printer, a BJ head driver for a bubble-jet printer, or thelike, for driving a printer, and a printer unit S including the driverR.

A bubble-jet recording system is a recording system for injecting inkdroplets by utilizing film boiling, and is disclosed in U.S. Pat. Nos.4,723,129 and 4,740,793.

The image processing circuit also includes a digitizer 58, the operationunit 1000, an operation interface 1000', RAMs 18 and 19, a CPU 20, a ROM21, a CPU bus 22, and I/O ports 500 and 501.

An original is irradiated with light emitted from an exposure lamp (notshown), and light reflected by the original is color-separated in unitsof color components, and read by the color read sensors 500a. The readcolor image signals are amplified to predetermined levels by the shiftregister (or amplifier circuit) 501a. The CCD driver 533a supplies pulsesignals for driving the color read sensors, and a necessary pulse sourceis generated by the system control pulse generator 534a.

FIGS. 3A and 3B respectively show the color read sensors and drivepulses. FIG. 3A shows the color read sensors used in this embodiment.Each color read sensor has 1,024 pixels in a main scan direction inwhich one pixel is defined as 63.5 μm (400 dots/inch (to be referred toas "dpi" hereinafter)) so as to read the main scan direction whiledividing it into five portions, and each pixel is divided into G, B, andR portions in the main scan direction. Thus, the sensor of thisembodiment has a total of 1,024×3=3,072 effective pixels. Chips 58 to 62are formed on a single ceramic substrate. First, third, and fifthsensors (or CCDs) (58a, 60a, and 62a) are arranged on a line LA, andsecond and fourth sensors are arranged on a line LB separated from theline LA by four lines (63.5 μm×4=254 μm). These sensors scan in adirection of an arrow AL in an original read mode.

Of the five CCDs, the first, third, and fifth CCDs are independently andsynchronously driven by a drive pulse group ODRV 118a, and the secondand fourth CCDs are independently and synchronously driven by a drivepulse group EDRV 119a. The pulse group ODRV 118a includes chargetransfer clocks O01A and O02A, and a charge reset pulse ORS, and thepulse group EDRV 119a includes charge transfer clocks E01A and E02A, anda charge reset pulse ERS. These clocks and pulses are completelysynchronously generated not to be jitters to prevent mutualinterferences and to attain noise reduction among the first, third andfifth pulses, and the second and fourth pulses. For this reason, thesepulses are generated by one reference oscillation source OSC 558a (FIG.2).

FIG. 4A is a circuit diagram of a CCD drive pulse generation circuit forgenerating the pulse groups ODRV 118a and EDRV 119a, and FIG. 4B is atiming chart of the CCD drive pulses. The CCD drive pulse generationcircuit is included in the system control pulse generator 534a shown inFIG. 2. A clock K0 135a obtained by frequency-dividing an original clockCLK0 generated by the single OSC 558a is used to generate referencesignals SYNC2 and SYNC3 for determining generation timings of pulsesODRV and EDRV. The output timings of the reference signals SYNC2 andSYNC3 are determined by setup values of presettable counters 64a and 65awhich are set by the CPU bus 22. The reference signals SYNC2 and SYNC3initialize frequency demultipliers 66a and 67a and drive pulsegeneration units 68a and 69a. The pulse groups ODRV 118a and EDRV 119acan be obtained as signals free from jitters since they are generatedwith reference to a signal HSYNC 118 input to this circuit on the basisof the clock CLK0 output from the single oscillation source OSC 558a andfrequency-divided clocks which are all synchronously generated, thuspreventing signal errors caused by interferences among sensors.

The synchronously obtained sensor drive pulses ODRV 118a are supplied tothe first, third, and fifth sensors 58a, 60a, and 62a, and the sensordrive pulses EDRV 119a are supplied to the second and fourth sensors 59aand 61a. The sensors 58a, 59a, 60a, 61a, and 62a independently outputvideo signals V1 to V5 in synchronism with the drive pulses. The videosignals V1 to V5 are amplified to predetermined voltage values byindependent amplifier circuits 501-1 to 501-5 in units of channels shownin FIG. 2. The amplified signals V1, V3, and V5 are output at a timingof a clock signal OOS 129a in FIG. 3B, and the amplified signals V2 andV4 are output at a timing of a clock signal EOS 134a, and these signalsare input to a video image processing circuit through a coaxial cable101a.

Color image signals obtained by reading an original while dividing theoriginal into five portions and input to the video image processingcircuit are separated into three colors, i.e., G (green), B (blue), andR (red) by the sample/hold (S/H) circuit 502a. Therefore, after S/Hprocessing, signals of 3×5=15 systems are subjected to signalprocessing.

The analog color signals sampled and held by the S/H circuit 502a inunits of R, G, and B are convened to digital signals in units of firstto fifth channels by the next A/D converter 503a. The digital signals ofthe first to fifth channels are parallelly and independently output tothe next circuit.

In this embodiment, since an original is read by the five staggeredsensors which have an interval of four lines (63.5 μm×4=254 μm) in a subscan direction, and correspond to five divided areas in the main scandirection, as described above, the preceding second and fourth channelsand the remaining first, third, and fifth channels have a positionalaberration. In order to normally connect outputs of these channels, thepositional aberration correction circuit 504a comprising a memory of aplurality of lines corrects the positional aberration.

A black correction operation in the black correction/white correctioncircuit 506a will be described below with reference to FIG. 5A. FIG. 5Bshows the principle of black correction. As shown in FIG. 5B, when alight amount input to the sensors is very small, the black level outputsof the first to fifth channels largely vary among chips and pixels. Ifthese signals are directly output to output an image, a stripe ornonuniform pattern is formed in a data portion of an image. Thus, avariation in black output must be corrected, and correction is performedby the circuit shown in FIG. 5A. Prior to the original read operation,the original scanning unit is moved to a position of the black platehaving a uniform density and arranged on a non-image region at thedistal end portion of an original table, and a halogen lamp is turned onto input a black level image signal to this circuit. As for a bluesignal B_(IN), in order to store this image data of one line in a blacklevel RAM 78a, a selector 82a selects an A input (d), a gate 80a isdisabled (a), and a gate 81a is enabled. More specifically, data lines151a, 152a and 153a are connected in the order named. Meanwhile, c isoutput to a selector 83a so that an output 154a of an address counter84a which is initialized by a signal HSYNC and counts clocks VCLK isinput to an address input 155a of the RAM 78a. Thus, a black levelsignal of one line is stored in the RAM 78a (the above operation will bereferred to as a black reference value fetch mode hereinafter).

In an image read mode, the RAM 78a is set in a data read mode, and dataof each pixel is read out and input to a B input of a subtracter 79a viadata lines 153a and 157a in units of lines. In this case, the gate 81ais disabled (b), and the gate 80a is enabled (a). The selector 86agenerates an A output. Therefore, for, e.g., the blue signal, a blackcorrection circuit output 156a is obtained as B_(IN) (i)-DK(i)=B_(OUT)(i) with respect to black level data DK(i) (to be referred to as a blackcorrection mode hereinafter). Similarly, the same control is performedfor a green signal G_(IN) and a red signal R_(IN) by circuits 77aG and77aR. Control lines a, b, c, d, and e for selector gates for attainingthis control are selected by a latch 85a assigned as I/Os of the CPU 20(FIG. 20) under the control of the CPU. When the selectors 82a, 83a, and86a select B inputs, the CPU 20 can access the RAM 78a.

White level correction (shading correction) in the blackcorrection/white correction circuit 506a will be described below withreference to FIGS. 6A to 6D. In white level correction, variations insensitivities of an illumination system, an optical system, and sensorsare corrected on the basis of white data obtained when the originalscanning unit is moved to a position of the uniform white plate andradiates light onto the white plate. FIG. 6A show a basic circuitarrangement. The basic circuit arrangement is the same as that shown inFIG. 5A. A difference between black and white correction operations isas follows. Black correction is performed by the subtracter 79a, whilein white correction, a multiplier 79a' is used. Thus, a description ofthe same parts will be omitted.

When the CCDs (500a) for reading an original are located at a readingposition of the uniform white plate (home position) in a colorcorrection mode, an exposure lamp (not shown) is turned on, and imagedata of a uniform white level is stored in a one-line correction RAM78a' prior to a copying operation or a reading operation. For example,if the main scan width corresponds to a width in a longitudinaldirection of an A4 size, 16×297 mm=4,752 pixels for 16 pels/mm, that is,the capacity of the RAM is at least 4,762 bytes, and data of the whiteplate in units of pixels are stored in the RAM 78a', as shown in FIG.6C, when white plate data Wi of an ith pixel (i=1 to 4,752) is as shownin FIG. 6B showing the principle of white correction.

A normal image read value Di of an ith pixel must be corrected withreference to Wi to obtain corrected data Do=Di×FF_(H) /Wi. The CPU 20outputs data to signal lines a', b', c', and d' of a latch 85a' so thatgates 80a' and 81a' are enabled, and selectors 82a', 83a', and 86a'select B inputs. As a result, the CPU 20 can access a RAM 78a'. In awhite correction sequence shown in FIG. 6D, the CPU 20 sequentiallycalculates FF_(H) /W0 for the start pixel W0, FF/W1 for a pixel W1, . .. , and substitutes data. When the CPU 20 completes calculations of ablue component of a color component image (step B in FIG. 6D), itsimilarly performs calculations for a green component (step G), and ared component (step R). Thereafter, the gate 80a' is enabled (a'), thegate 81a' is disabled (b'), and the selectors 83a' and 86a' select Ainputs, so that Do=Di×FF_(H) /Wi is output in response to input originalimage data Di. Coefficient data FF_(H) /Wi read out from the RAM 78a' ismultiplied with original image data 151a' from one input terminal viasignal lines 153a' and 157a', and the product is then output.

As described above, black and white levels are corrected on the basis ofvarious factors such as a black level sensitivity of an image inputsystem, a variation in dark current of CCDs, a variation in sensitivityamong sensors, a variation in light amount of an optical system, a whitelevel sensitivity, and the like, and image data B_(OUT) 101, G_(OUT)102, and R_(OUT) 103 whose white and black levels are uniformlycorrected in units of colors in the main scan direction are obtained.The black- and white-level corrected color separation image data aresupplied to the color conversion circuit B for detecting a pixel havinga specific color density or a specific color ratio upon instruction froman operation unit (not shown), and converting the detected data intoanother color density or ratio instructed by the operation unit.

<Color Conversion>

FIG. 7 is a block diagram of the color conversion (gradation colorconversion and density color conversion) unit. The circuit shown in FIG.7 comprises a color detection unit 5b for judging an arbitrary color setin a register 6b by the CPU 20 from 8-bit color separation signalsR_(IN), G_(IN), and B_(IN) (1b to 3b), an area signal Ar 4b forperforming color detection and color conversion at a plurality ofpositions, line memories 10b and 11b for performing processing forexpanding a signal of "specific color" output from the color detectionunit (to be referred to as a hit signal hereinafter) in a main or subscan direction (only in the sub scan direction in FIG. 7), an OR gate12b, line memories 13b to 16b for synchronizing a color conversionenable signal 33b with input color separation data (R_(IN), G_(IN), andB_(IN) 1b to 3b) and the area signal Ar 4b, delay circuits 17b to 20b,and a color conversion unit 25b for performing color conversion on thebasis of the enable signal 33b, the synchronized color separation data(R_(IN) ', G_(IN) ', and B_(IN) ' 21b to 23b), an area signal Ar 24b,and color-convened color data set in a register 26b. The colorconversion enable signal 33b is generated by an AND gate 32b based onthe expanded hit signal 34b and a non-rectangular signal (includingrectangle) BHi 27b. A hit signal H_(OUT) 31b is output in synchronismwith color-converted color separation data (R_(OUT), G_(OUT), andB_(OUT) 28b to 30b).

An algorithm of gradation color judgement and gradation color conversionwill be briefly described below. Note that gradation color judgement orconversion means that color judgement or conversion of colors having thesame hue is performed so that color conversion is performed whilepreserving a density value of colors having the same hue.

As the same color (or hue), it is known that ratios of a red signal R₁,a green signal G₁, and a blue signal B₁ are equal to each other.

Thus, data M₁ of one (maximum value color, to be referred to as a maincolor hereinafter) of colors to be color-converted is selected, andratios of the selected color to the remaining two color data arecalculated. For example, when the main color is R, M₁ =R to calculate G₁/M₁ and B₁ /M₁.

A pixel in which the following relations are established for input dataR_(i), G_(i), and B_(i) is determined as a pixel to be color-converted:##EQU1##

For color-converted data (R₂, G₂, and B₂), ratios of data M₂ of a maincolor to the remaining two color data are calculated.

For example, when G₂ is a main color, M₂ =G₂, and R₂ /M₂ and B₂ /M₂ arecalculated.

For the main color M₁ of input data, M₁ ×(R₂ /H₂) and M₁ ×(B₂ /M₂) arecalculated.

If data represents a pixel to be color-converted, (M₁ ×(R₂ /M₂), M₁, andM₁ ×(B₂ /M₂)) are output; if it does not represent a pixel to becolor-converted, (R_(i), G_(i), and B_(i)) are output.

Thus, all the same hue portions having gradation are detected, andcolor-converted data according to the gradation can be output.

FIG. 8 is a block diagram showing a color judgement circuit. Thiscircuit detects a pixel to be color-converted.

The circuit shown in FIG. 8 includes a smoothing unit 50b for smoothinginput data R_(IN) b1, G_(IN) b2, and B_(IN) b3, a selector 51b forselecting one (main color) of the outputs from the smoothing unit,selectors 52b_(R), 52b_(G), and 52b_(B) each for selecting one of theoutput from the selector 51b and a fixed value R₀, G₀, or B₀, OR gate54b_(R), 54b_(G), or 54b_(B), selectors 63b, 64b_(R), 64b_(G), and64b_(B) for setting a select signal in the selectors 51b, 52b_(R),52b_(G), and 52b_(B) based on area signals Ar 10 and Ar 20, andmultipliers 56b_(R), 56b_(G), 56b_(B), 57b_(R), 57b_(G), and 57b_(B) forcalculating upper and lower limits.

Upper limit ratio registers 58b_(R), 58b_(G), and 58b_(B), and lowerlimit ratio registers 59b_(R), 59b_(G), and 59b_(B) set by the CPU 20can be set up with data for performing color detection of a plurality ofareas on the basis of an area signal Ar 30.

The area signals Ar 10, Ar 20, and Ar 30 are signals generated based onthe area signal Ar 4b shown in FIG. 7, and are respectively outputthrough necessary numbers of DF/Fs. The circuit of FIG. 8 also includesan AND gate 61b, an OR gate 62b, and a register 67b.

An actual operation will be described below. One of data R', G', and B'obtained by smoothing data R_(IN) b1, G_(IN) b2, and B_(IN) b3 isselected by the selector 51b based on a select signal S₁ set by the CPU20, thereby selecting main color data. Note that the CPU 20 setsdifferent data A and B in registers 65b and 66b, the selector 63bselects one of the data A and B in accordance with the signal Ar 10, andsends the selected data as the select signal S₁ to the selector 51b.

In this manner, the two registers 65b and 66b are prepared, thedifferent data are input to the A and B inputs of the selector 63b, andone of these data is selected in accordance with the area signal Ar 10.With this arrangement, color detection can be separately performed for aplurality of areas. The area signal Ar 10 need not be a signal for onlya rectangular area but can be one for a non-rectangular area.

Each of the next selectors 52b_(R), 52b_(G), and 52b_(B) selects one ofdata R₀, G₀, or B₀ set by the CPU 20 and the main color data selected bythe selector 51b in accordance with a select signal generated based onoutputs 53ba to 53bc from a decoder 53b and a fixed color mode signalS₂. Note that the selectors 64b_(R), 64b_(G), and 64b_(B) select one ofthe data A and B in accordance with the area signal Ar 20, so that theycan detect different colors for a plurality of areas as in the selector63b. In this case, the data R₀, G₀, and B₀ are selected in conventionalcolor conversion (fixed color mode) and for a main color in gradationcolor judgement, and the main color data is selected for colors otherthan the main color in gradation color conversion.

An operator can desirably select fixed or gradation color judgement froman operation unit. Alternatively, the fixed or gradation color judgementcan be switched in a software manner on the basis of color data(non-convened color data) input from an input device, e.g., a digitizer.

The outputs from these selectors 52b_(R), 52b_(G), and 52b_(B) and upperand lower limit values of data R', G', and B' from the upper limit ratioregisters 58b_(R), 58b_(G), and 58b_(B) and the lower limit ratioregisters 59b_(R), 59b_(G), and 59b_(B) are multiplied with each otherby multipliers 56b_(R), 56b_(G), and 56b_(B), and 57b_(R), 57b_(G), and57b_(B), and the products are set in window comparators 60b_(R),60b_(G), and 60b_(B).

The AND gate 61b checks if main color data falls within a predeterminedrange, and two colors other than the main color fall within apredetermined range in the window comparators 60b_(R), 60b_(G), and60b_(B). The register 67b can set "1" according to an enable signal 68bfrom the judgement unit regardless of a judgement signal. In this case,a color to be converted is present in a portion which is set to be "1".

With the arrangement, fixed or gradation color judgement can beperformed for a plurality of areas.

FIG. 9 is a block diagram of a color conversion circuit. This circuitselects a color-converted signal or an original signal on the basis ofthe output 7b from the color detection unit 5b.

In FIG. 9, the color conversion unit 25b comprises a selector 111b,registers 112b_(R1), 112b_(R2), 112b_(G1), 112b_(G2), 112b_(B1), and112b_(B2) in each of which a ratio of a converted color to main colordata (maximum value) is set, multipliers 113b_(R), 113b_(G), and113b_(B), selectors 114b_(R), 114b_(G), and 114b_(B), selectors115b_(R), 115b_(G), and 115b_(B), an AND gate 32b, selectors 117b,112b_(R), 112b_(G), 112b_(B), 116b_(R), 116b_(G), and 116b_(B) forsetting data, which is set by the CPU 20 in accordance with area signalsAr 50, Ar 60, and Ar 70 generated based on the area signal Ar' 24 inFIG. 7, in the selector 111b, the multipliers 113b_(R), 113b_(G), and113b_(B), the selectors 114b_(R), 114b_(G), 114b_(B), respectively, anda delay circuit 118b.

The actual operation will be described below.

The selector 111b selects one (main color) of input signals R_(IN) '21b, G_(IN) ' 22b, and B_(IN) ' 23b in accordance with a select signalS5. The signal S5 is generated such that an area signal Ar 40 causes theselector 117b to select one of A and B inputs corresponding to two dataset by the CPU 20. In this manner, color conversion processing for aplurality of areas can be achieved.

The signal selected by the selector 111b is multiplied with registervalues set by the CPU 20 by the multipliers 113b_(R), 113b_(G), and113b_(B). In this case, the area signal Ar 50 causes the selectors112_(R), 112b_(G), and 112b_(B) to select pairs of register values112b_(R1).112b_(R2), 112b_(G1).112b_(G2), and 112b_(B1).112b_(B2), thusalso achieving color conversion processing for a plurality of areas.

Each of the selectors 114b_(R), 114b_(G), and 114b_(B) selects one ofthe products and a fixed value selected by the selector 116b_(R),116b_(G), or 116b_(B) from a pair of fixed values R_(o) '.R_(o) ", G_(o)'.G_(o) ", or B_(o).B_(o) " set by the CPU 20 in accordance with a modesignal S6. In this case, the mode signal S6 is selected by the areasignal Ar 60 in the same manner as in the signal S5.

Finally, each of the selectors 115b_(R), 115b_(G), and 115b_(B) selectsone of data R_(IN) ", G_(IN) ", and B_(IN) " (obtained by delaying thedata R_(IN) ', G_(IN) ', and B_(IN) ' to adjust timings) and the outputfrom the selector 114b_(R), 114b_(G), or 114b_(B). As a result, dataR_(OUT), G_(OUT), and B_(OUT) are output. In addition, a hit signalH_(OUT) is also output in synchronism with the data R_(OUT), G_(OUT),and B_(OUT).

A select signal S_(B) ' is obtained by delaying an AND product of acolor judgement result 34b and a color conversion enable signal BHi 34b.As the signal BHi, for example, a non-rectangular enable signal as adotted line in FIG. 10 is input, so that color conversion processing canbe performed for a non-rectangular area. In this case, an area signal isgenerated on the basis of an area indicated by an alternate long andshort dashed line, i.e., coordinates of an uppermost left position ("a"in FIG. 10), an uppermost right position ("b" in FIG. 10), a lowermostleft position ("c" in FIG. 10), and a lowermost left position ("d" inFIG. 10). The non-rectangular area signal BHi is an area signal which isinput from an input device such as a digitizer, and is developed in the100-dpi binary memory L. When color conversion is performed using thenon-rectangular enable signal, an enable area can be designated along aboundary of a portion to be converted. Therefore, a color detectionthreshold range can be widened as compared to conventional colorconversion using a rectangle. Therefore, a detection power can beincreased, and an output image subjected to gradation color conversionwith high precision can be obtained.

Color conversion having a lightness according to a main color of thecolor detection unit 5b (for example, when red isgradation-color-converted to blue, light red is converted to light blue,and dark red is converted to dark blue) or fixed value color conversioncan be desirably performed for a plurality of areas.

As will be described later, mosaic processing, texture processing,trimming processing, masking processing, and the like can be executedfor only an area (non-rectangular or rectangular area) of a specificcolor on the basis of the hit signal H_(OUT).

The area signals Ar 10, Ar 20, and Ar 30 are generated based on the areasignal Ar 4b, and the area signals Ar 40, Ar 50, Ar 60, and Ar 70 aregenerated based on the area signal Ar' 24b. These signals are generatedbased on an area signal 134 from the area signal generation circuit J(FIG. 2). These signals need not always be rectangular area signals butmay be non-rectangular area signals. More specifically, thenon-rectangular area signal BHi stored in the 100-dpi binary memory andbased on non-rectangular area information maybe used.

A method of generating the signal BHi will be described later. Thesignal BHi can include both rectangular and non-rectangular areasignals.

As described above, according to this embodiment, since a colorconversion area can be set based not only on a rectangular area signalbut also on a non-rectangular area signal, color conversion processingcan be executed with higher precision.

As shown in FIG. 2, the outputs 103, 104, and 105 from the colorconversion circuit B are supplied to the LOG conversion circuit C forconverting image data proportional to a reflectance to density data, thecharacter/image area separation circuit I for discriminating a characterarea, a halftone area, and a dot area on an original, and the externalapparatus interface M for causing this system to communicate data withan external apparatus through cables 135, 136, and 137.

Input color image data proportional to a light amount is input to theLOG conversion circuit C (FIG. 2) to match it with spectral luminousefficiency characteristics of human eyes.

In this circuit, the data is converted so that white=00_(H) andblack=FF_(H). Since input gamma characteristics vary depending on typesof image source input to the image read sensor, e.g., a normalreflective original, a transparent original for, e.g., a film projector,a transparent original of another type, e.g., a negative film, apositive film, or a film sensitivity, or an exposure state, a pluralityof LOG conversion LUTs (Look-Up Tables) are prepared, as shown in FIGS.11A and 11B, and are selectively used according to applications. TheLUTs are selected by signal lines lg0, lg1, and lg2 in accordance withan instruction input from the operation unit 1000 or the like as an I/Oport. Data output for B, G, and R correspond to density values of anoutput image. Since signals B (blue), G (green), and R (red) correspondto toner amounts of Y (yellow), M (magenta), and C (cyan), the followingimage data correspond to yellow, magenta, and cyan.

A color correction circuit performs color correction of color componentimage data from an original image obtained by the LOG conversion, i.e.,yellow, magenta, and cyan components as follows. It is known thatspectral characteristics of color separation filters arranged incorrespondence with pixels in the color read sensors have unnecessarytransmission regions, as indicated by hatched portions in FIG. 13, andcolor toners (Y, M, and C) transferred to a transfer sheet haveunnecessary absorption components, as shown in FIG. 14. Thus, as is wellknown, masking correction is executed to calculate the following linearequation of the color-component image data Yi, Mi, and Ci to performcolor correction: ##EQU2## Furthermore, a black addition operation forcalculating Min(Yi, Mi, Ci) (minimum value of Yi, Mi, and Ci) using Yi,Mi, and Ci, and adding a black toner based on the calculated value as ablack component, and an undercolor removal (UCR) operation fordecreasing amounts of color agents to be added in accordance with anamount of an added black component are often executed. FIG. 12A shows acircuit arrangement of the color correction circuit D for performingmasking, black addition, and UCR. The characteristic features of thisarrangement are:

(1) This arrangement has two systems of masking matrices, and thesematrices can be switched at high speed according to "1/0" of one signalline.

(2) The presence/absence of UCR can be switched at high speed accordingto "1/0" of one signal line.

(3) This arrangement has two systems of circuits for determining a blacktoner amount, and these circuits can be switched at high speed accordingto "1/0" of a signal line.

Prior to image reading, desired first and second matrix coefficients M₁and M₂ are set by a bus connected to the CPU 20. In this embodiment, wehave: ##EQU3## The matrix coefficients M₁ are set in registers 87d 95d,and the coefficients M₂ are set in registers 96d to 104d.

Each of selectors 111d to 122d, 135d, 131d, and 136d selects an A inputwhen its S terminal="1"; select a B input when its S terminal="0".Therefore, when the matrix M₁ is selected, a switching signal MAREA 364is set to be "1"; when the matrix M₂ is selected, the signal 364 is setto be "0".

A selector 123d obtains outputs a, b, and c based on the truth tableshown in FIG. 12B according to select signals C₀ and C₁ (366d and 367d).The select signals C₀, C₁, and C₂ are set to be (C₂, C₁, C₀)=(0, 0, 0),(0, 0, 1), (0, 1, 0), and (1, 0, 0), and (0, 1, 1) for a monochromesignal in the order of, e.g., Y, M, C, and Bk, thereby obtainingdesirably color-corrected color signals. Assuming that (C₀, C₁, C₂)=(0,0, 0) and MAREA="1", the contents of the registers 87d, 88d, and 89d,i.e., (a_(Y1), -b_(M1), -c_(C1)) appear at the outputs (a, b, c) of theselector 123d. On the other hand, a black component signal 374dcalculated by Min(Yi, Mi, Ci)=k based on the input signals Yi, Mi, andCi undergoes linear conversion given by Y=ax-b (where a and b areconstants) by a linear converter 137d, and the obtained signal is inputto B inputs of subtracters 124d, 125d, and 126d. The subtracters 124d to126d calculate Y=Yi-(ak-b), M=Mi-(ak-b), and C=Ci-(ak-b) as UCRprocessing, and output the results to multipliers 127d, 128d, and 129dfor performing masking calculations.

The multipliers 127d, 128d, and 129d receive (a_(Y1), -b_(M1), -c_(C1))at their A inputs, and the above-mentioned Yi-(ak-b), Mi-(ak-b),Ci-(ak-b)!= Yi, Mi, Ci! at their B inputs. Thus, as can be seen fromFIG. 12A, Y_(OUT) =Yi×(a_(Y1))+Mi×(-b_(M1))+Ci×(-c_(C1)) is obtainedunder the condition of C₂ =0 (Y or M or C). Thus, yellow image datasubjected to masking color correction and UCR processing is obtained.Similarly, the following data are output to D_(OUT) :

    M.sub.OUT =Yi×(-a.sub.Y2)+Mi×(-b.sub.M2)+Ci×(-c.sub.C2)

    C.sub.OUT =Yi×(-a.sub.Y3)+Mi×(-b.sub.M3)+Ci×(-c.sub.C3)

Color selection is controlled by the CPU 20 in accordance with an outputorder to a color printer and the truth table shown in FIG. 12B based on(C₀, C₁, C₂). Registers 105d to 107d, and 108d to 110d are used to forma monochromatic image. An output can be obtained by performing weightingaddition of colors by MONO=k₁ Yi+l₁ Mi+m₁ Ci.

When a Bk signal is output, C₂ =1 according to the select signal C₂(368) input to the selector 131d, that is, a Bk signal is subjected tolinear conversion given by Y=cx-d by a linear converter 133d, and isoutput from the selector 131d. A black component signal BkMj 110 isoutput to an outline portion of a black character on the basis of theoutput from the character/image area separation circuit I (to bedescribed later). Color switching signals C₀ ', C₁ ', and C₂ ' 366 to368 are set by an output port 501 connected to the CPU bus 22, and thesignal MAREA 364 is output from the area signal generation circuit J.Gate circuits 150d to 153d control so that when DHi="1" based on thenon-rectangular area signal DHi 22 read out from a binary memory (bitmap memory) L537, signals C₀ ', C₁ ', C₂ '="1, 1, 0", therebyautomatically outputting data for a monochromatic image.

<Character/Image Area Separation Circuit>

FIG. 15A shows the character/image area separation circuit I. Thecharacter/image separation circuit I checks using read image data if theimage data represents a character or an image or in chromatic orachromatic color. The processing flow of this circuit will be describedbelow with reference to FIGS. 15A to 15C.

The data R (red) 103, G (green) 104, and B (blue) 105 input from thecolor conversion circuit B to the character/image area separationcircuit I are input to a minimum value detection circuit MIN(R,G,B)101I, and a maximum value detection circuit MAX(R,G,B) 102I. Theseblocks select maximum and minimum values based on three differentluminance signals of input R, G, and B data. A difference between theselected signals is calculated by a subtracter 104I. If the differenceis large, i.e., when input R, G, and B data are not uniform, itindicates that input signals are not achromatic color signalsrepresenting black or white but chromatic color signals deviated to acertain color. Of course, when the difference is small, the R, G, and Bsignals are at almost the same levels, and are achromatic signals whichare not deviated to a certain color. This difference signal is output toa delay circuit Q as a gray signal GR 125. This difference is comparedwith a threshold value arbitrarily set in a register 111I by the CPU 20by a comparator 121I, and a comparison result is output to the delaycircuit Q as a gray judgement signal GRBi 126. The phases of thesesignals GR 125 and GRBi 126 are matched with those of other signals bythe delay circuit Q. Thereafter, these signals are input to thecharacter/image correction circuit E (to be described later), and areused as processing judgement signals.

Meanwhile, the minimum value signal obtained by the circuit MIN(R,G,B)101I is also input to an edge emphasis circuit 103I. The edge emphasiscircuit 103I performs the following calculation using adjacent pixeldata in the main scan direction, thereby performing edge emphasis:##EQU4## D_(OUT) : edge-emphasized image data D_(i) : ith pixel data

Note that the edge emphasis is not limited to the above-mentionedmethod, and various other known methods may be used. Line memories forperforming a delay of 2 lines or 5 lines in the sub scan direction arearranged, and a 3×3 or 5×5 pixel block is used, so that normal edgeemphasis can be performed. In this case, the edge emphasis effect can beobtained not only in the main scan direction but also in the sub scandirection. Thus, the edge emphasis effect can be enhanced. With thisedge emphasis, precision of black character detection (to be describedbelow) can be effectively improved.

The image signal which is edge-emphasized in main scan direction is thensubjected to average value calculations in 5×5 and 3×3 pixel windows by5×5 and 3×3 average circuits 109I and 110I. Line memories 105I to 108Iare subscan delay memories for performing average value processing. Theaverage value of a total of 5×5=25 pixels calculated by the 5×5 averagecircuit 109I is added to offset values independently set in offset unitsconnected to the CPU bus 22 by adders 115I, 120I, and 125I. The added5×5 average values are input to a limiter 1 (113I), a limiter 2 (118I),and a limiter 3 (123I). The limiters are connected to the CPU bus 22,and limiter values can be independently set in these limiters. When the5×5 average value is larger than a setup limiter value, an output isclipped by the limiter value. The output signals from the limiters arerespectively input to a comparator 1 116I, a comparator 2 121I, and acomparator 3 126I. The comparator 1 116I compares the output from thelimiter 1 113I with the output from the 3×3 average circuit 110I. Thecomparison output of the comparator 1 116I is input to a delay circuit117I, so that its phase is to be matched with an output signal from adot area judgement circuit 122I (to be described later). The signal isbinarized using average values of the 5×5 and 3×3 pixel blocks in orderto prevent painting and omissions caused by the MTF at a predetermineddensity or more, and is filtered through a 3×3 low-pass filter, so thathigh-frequency components of a dot image are cut so as not to detectdots of the dot image upon binarization.

The output signal from the comparator 2 (121I) is subjected tobinarization with through image data so as to detect high-frequencycomponents of an image, so that a dot area can be detected by the nextdot area judgement circuit 122I. The dot area judgement circuit 122Irecognizes a dot from a direction of an edge since a dot image isconstituted by a set of dots, and counts the number of dots around it,thereby detecting a dot image. More specifically, the circuit 122Iperforms dot judgement as follows.

Dot Judgment!

The dot area judgement circuit 122I will be described below withreference to FIG. 15B. A signal 101J binarized by the comparator 2(121I) of the character/image area separation circuit (FIG. 15A) isdelayed by one line in each of one-line delay memories (FIFO memories)102J and 103J shown in FIG. 15B. Thus, the binary signal 101J, and thesignals delayed by the FIFO memories 102J and 103J are input to an edgedetection circuit 104J. The edge detection circuit 104J independentlydetects edge directions for a total of four directions, i.e., vertical,horizontal, and two oblique directions with respect to an objectivepixel. After the edge directions are quantized in 4 bits by the edgedetection circuit, the 4-bit edge signal is input to a dot detectioncircuit 109J and a one-line delay memory (FIFO memory) 105J. 4-bit edgesignals delayed by one line each by the FIFO memory 105J, and one-linedelay memories (FIFO memories) 106J, 107J, and 108J are input to the dotdetection circuit 109J. The dot detection circuit 109J judges based onsurrounding edge signals whether or not an objective pixel is a dot. Forexample, as indicated by hatched portions in the dot detection circuit109J in FIG. 15B, a total of seven pixels of previous two linesincluding an objective pixel include at least one pixel corresponding toan edge in a ⊥ direction (a density gradient is present in a directionof the objective pixel), and a total of seven pixels (pixels) of thefollowing two lines including the objective pixel include at least onepixel corresponding to an edge in a direction (a density gradient ispresent in the direction of the objective pixel). In addition, whenthere are edges of ├ and ┤ or ┤ and ├ in the horizontal direction, it isdetermined as a dot. A dot is determined when and ⊥. After the dotjudgement result is similarly delayed by one-line delay memories 110Jand 111J, the delayed results are fattened by a fattening circuit 112J.When there is at least one pixel which is determined as a dot in a totalof 12 pixels (=3 lines×4 pixels), the fattening circuit 112J judges theobjective pixel as a dot regardless of the judgement result of theobjective pixel. The fattened dot judgement result is delayed by oneline by each of one-line delay memories 113J and 114J. The output fromthe fattening circuit 112J and the signal delayed by a total of twolines by the one-line delay memories 113J and 114J are input to amajority-rule decision circuit 115J. The majority-rule decision circuit115J samples every four pixels from lines before and after a lineincluding the objective pixel. The circuit 115J samples pixels from60-pixel widths on the right and left sides of the objective pixel, thatis, samples 15 pixels each from the right and left pixel widths, i.e., atotal of 30 pixels from two lines, thereby calculating the number ofpixels which are judged as dots. If the calculated value is larger thana preset value, it can be determined that the objective pixel is a dot.

In the copying machine of this embodiment, a moving speed of the imagereading unit of the image reader is changed according to a magnificationin the sub scan direction (sheet feed direction). In this case, in orderto perform accurate dot judgement, FIFO memory control of the one-linedelay memories 102J, 103J, 105J, 106J, 107J, 108J, 110J, 111J, 113J, and114J is performed up to a predetermined magnification such that writeaccess is made for one of two lines, and now rite access is made for theother line.

Since the write access of the FIFO memories is controlled in thismanner, dot judgement can be performed using an equi-magnification imageeven in a zoom mode. Thus, judgement precision in the zoom mode can beimproved. The types of filters for edge detection, the sizes of matricesof the dot detection circuits, the fattening circuit, and themajority-rule decision circuit are not limited to those described in theabove embodiment, and sub scan thinning in the zoom mode may beperformed every three lines. Thus, various modifications may be made.

Sampling in an enlargement state will be described below with referenceto FIG. 15C. 1 of FIG. 15C shows an original image. When an image isread at an equi-magnification, an original image is read within dottedlines shown in 1 in FIG. 15C. This image is continuously written in theFIFO memories in units of lines. More specifically, as shown in 2 inFIG. 15C, all the line data are written in the FIFO memories withoutomissions. An enlargement state will be described below. For the sake ofsimplicity, a 200% enlargement state will be described. As describedabove, the moving speed of the reading unit is decreased in theenlargement state. For this reason, in the 200% enlargement state, themoving speed is halved, and a one-line image is read by a width half aone-line width. 3 in FIG. 15C shows a read image in correspondence withan original image.

As shown in 4 in FIG. 15C, the read image data is written in the FIFOmemories in the same manner as in the equi-magnification state. In thisstate, write access of the FIFO memories is performed while data isthinned every other lines, as shown in 4 in FIG. 15C.

In this embodiment, the 200% enlargement state has been described. Writeaccess is performed once per two lines. This write method can bemodified according to a magnification in the zoom mode.

The judgement result from the dot area judgement circuit 122I and thesignal from the delay circuit 117 are locally ORed by an OR gate 129I.An error judgement is eliminated from the logical sum by an errorjudgement and elimination circuit 130I, and the obtained signal isoutput to art AND gate 132I. The OR gate 129I outputs a judgement signalwhich is judged as a halftone area or a dot area. By utilizing acharacteristic that a small area is present in a character, and a largearea is present in an image such as a photograph, the error judgementand elimination circuit 130I thins an image area, and eliminatesisolated image areas. More specifically, if there is at least one pixelother than that of an image such as a photograph within a 1 (mm)×1 (mm)area around a central pixel xij, it is determined that the central pixelfalls outside an image area. More specifically, binary signals withinthe area are logically ANDed, and only when all "1"s are obtained, thecentral pixel xij=1 is set. After isolated image areas are removed inthis manner, the fattening processing is executed to recover the thinnedimage area. More specifically, if there is at least one pixel of animage area such as a photograph within a 2 (mm)×2 (mm) area, the centralpixel xij is determined as an image area. In the fattening processing,thinned binary signals are logically ORed within the area, and when atleast one pixel is "1" (image area), the central pixel xij=1 is set.

The error judgement and elimination circuit 130I outputs an invertedsignal of the fattened binary signal. The inverted signal serves as amask signal of halftone and dot images.

Similarly, the output from the dot area judgement circuit 122I isdirectly input to an error judgement and elimination circuit 131I and issubjected to thinning processing and fattening processing.

Note that the mask size of the thinning processing is set to be equal toor smaller than that of the fattening processing, so that the fattenedjudgement result can cross. More specifically, in both the errorjudgement and elimination circuits 130I and 131I, after thinningprocessing using a 17×17 pixel mask, another thinning is executed usinga 5×5 pixel mask. Thereafter, fattening processing is executed using a34×34 pixel mask. An output signal SCRN 127 from the error judgement andelimination circuit 131I serves as a judgement signal for executingsmoothing processing of only a dot judgement portion in thecharacter/image correction circuit E (to be described later) and forpreventing moire of a read image.

An output signal from the comparator 3 126I is subjected to outlineextraction so as to obtain a sharp character in the next circuit. As anextraction method, the binarized output of the comparator 3 126I issubjected to thinning processing and fattening processing using a 5×5pixel block, and a difference between the fattened and thinned signal isdetermined as an outline. An outline signal extracted in this manner isinput to a delay circuit 128I so that its phase is matched with the masksignal output from the error judgement and elimination circuit 130I.Thereafter, a portion of the outline signal, which is judged as animage, is masked by the mask signal by an AND gate 132I, therebyoutputting an outline signal of an original character portion. Theoutput from the AND gate 132I is output to an outline regeneration unit133I.

The reason why average values in the 5×5 and 3×3 windows are calculated,as described above, is to detect a halftone area. The matrix sizes andwindow sizes are not limited to those described above, and averagevalues of two different areas including an objective pixel need only becalculated.

The matrix sizes of the thinning processing and fattening processing inthe error judgement and elimination circuits 130I and 131I can also bearbitrarily set.

As described above, according to the outline edge extraction algorithmof this embodiment, not only a frame signal is extracted but also it islogically ANDed with a mask signal based on a halftone or dot signal.Thus, character/image areas can be separated with high precision.

Since appropriate offsets can be set in average values of 5×5 pixelblocks used in detection of halftone, dot, and character areas by theCPU 20, these areas can be precisely detected.

Furthermore, according to this embodiment, since the output signal fromthe dot area judgement circuit and a binary signal indicating a dot orhalftone area are subjected to thinning processing and fatteningprocessing to eliminate error judgement, an error judgement portion canbe eliminated from the area signal, and image area separation can beperformed with high precision.

Since a signal used in character/image area separation is the Min(R,G,B)signal, three colors, i.e., R, G, and B information can be effectivelyused as compared to a case wherein a luminance signal Y is used. Inparticular, character/image separation in a yellowish image can beperformed with high precision.

Since the edge-emphasized Min(R,G,B) signal is subjected tocharacter/image area separation, a character portion can be easilydetected, and error judgement can be easily prevented.

<Outline Regeneration Unit>

The outline regeneration unit 133I executes processing for converting apixel which is not judged as a character outline portion into acharacter outline portion based on information of surrounding pixels,and sends a resultant MjAr 124 to the character/image correction circuitE to execute processing, as will be described later.

More specifically, as shown in FIGS. 16A to 16E, as for a thickcharacter (FIG. 16A), a dotted line portion in FIG. 16B is judged as acharacter portion, and is subjected to processing to be described later.As for a thin character (FIG. 16C), however, a character portion isjudged like a dotted line portion in FIG. 16D, and gaps are formed inthe character portion, as indicated by hatching in FIG. 16D. Therefore,if such a character is subjected to the processing to be describedlater, error judgement occurs, and the obtained character is not easy toread. In order to prevent this, outline regeneration processing forconverting a portion which is not determined as a character into acharacter portion based on surrounding information is performed. Morespecifically, hatched portions are determined as character portions, sothat the character portions can be regenerated, as shown in FIG. 16E. Asa result, error judgement can be eliminated for characters in colorswhich are not easy to detect or for thin characters, and image qualitycan be improved.

FIGS. 17A to 17H show how to regenerate an objective pixel in acharacter portion using surrounding information. In FIGS. 17A to 17D, anobjective pixel is determined as a character portion regardless of itsinformation when two pixels vertically, horizontally, or obliquelyadjacent to an objective pixel in a 3×3 pixel block are characterportions (both S₁ and S₂ ="1"). In FIGS. 17E to 17H, an objective pixelis determined as a character portion regardless of its information whentwo pixels adjacent to those horizontally, vertically, or obliquelyadjacent to an objective pixel in a 5×5 pixel block are characterportions (both S₁ and S₂ ="1"). In this manner, two stages (a pluralityof types of blocks) of structures can overcome errors in a wide range.The size and number of pixel blocks, and types of filter can bevariously modified. For example, a 7×7 pixel block may be employed.

FIGS. 18 and 19 show the outline regeneration unit for realizing theprocessing shown in FIGS. 17A to 17H. The circuit shown in FIGS. 18 and19 comprises line memories 164i to 167i, DF/Fs 104i to 126i forobtaining information around an objective pixel, AND gates 146i to 153ifor realizing FIGS. 17A to 17H, and an OR gate 154i.

The four line memories and the 23 DF/Fs extract information of thepixels S₁ and S₂ in FIGS. 17A to 17H. The AND gates 146i to 153i can beindependently enabled/disabled by registers 155i to 162i correspondingto operations of FIGS. 17A to 17H. Note that signals of the registersare controlled by the CPU 20.

The correspondences between the AND gates 146i to 153i and FIGS. 17A to17H are as follows: ##STR1##

FIG. 20 shows a timing chart of a signal WE (EN1) and a signal RE (EN2)of the line memories 164i to 167i. The signals EN1 and EN2 are generatedat the same timing in an equi-magnification mode, and the signal WE iswritten once per two thinned lines in an enlargement mode (e.g., 200% to300%). A thinning amount can be arbitrarily determined. Thus, the sizesof FIGS. 17A to 17H can be expanded. In the enlargement mode,information is input to the line memories as an image enlarged in onlythe sub scan direction. Thus, the sizes of FIGS. 17A to 17H areexpanded, so that processing can be executed using an equi-magnificationimage even in the enlargement mode.

FIGS. 17I to 17N are views for explaining this in more detail. FIG. 17Ishows a shape of an outline regeneration filter of a 3×3 pixel block inan equi-magnification mode. When A=B=1 or C=D=1 or E=F=1, an objectivepixel is forcibly set to be 1, i.e., a character outline.

FIG. 17J shows a shape of an 200% outline regeneration filter, andcorresponds to a 3×3 pixel block in the equi-magnification mode. Thisblock is generated as described above. A to F respectively correspond toA' to F'. That is, A' to F' are set every other lines in the sub scandirection, so that character/image areas can be separated under the samecondition as in the equi-magnification mode even in a zoom mode.

FIGS. 17H to 17N show practical applications. Assume that FIG. 17M showsan input of the outline regeneration unit in the equi-magnificationmode, and FIG. 17N shows an input in a 200% mode. When FIG. 17I isapplied to FIG. 17N, since E=F=I, 1 can become "1", and an outline shownin FIG. 17K can be obtained. On the other hand, when FIG. 17J is appliedto FIG. 17N, since E'=F'=1, 1' and 1" become "1", and an outline shownin FIG. 17L is obtained. In the enlargement mode, an outlineregeneration block is formed using thinned data to execute regenerationprocessing, so that outline regeneration having the same detection powercan be performed in both the 200% enlargement mode and theequi-magnification mode.

In this embodiment, 200% enlargement has been exemplified. The sameprocessing can be executed when a magnification is changed.

<Character/Image Correction Circuit>

The character/image correction circuit E executes the followingprocessing for a black character, a color character, a dot image, and ahalftone image on the basis of the judgement signal generated by thecharacter/image area separation circuit I.

Processing 1! Processing for Black Character

1-1! The signal BkMj 112 obtained by black extraction is used as a videosignal.

1-2! Y, M, and C data are subjected to subtraction according to themulti-value achromatic signal GR 125 or a setup value. Bk data issubjected to addition according to the multi-value achromatic signal GR125 or a setup value.

1-3! Edge emphasis is executed.

1-4! A black character is printed at a high resolution of 400 lines (400dpi).

1-5! Color residual removal processing (to be described later) isexecuted.

Processing 2! Processing for Color Character

2-1! Edge emphasis is executed.

2-2! A color character is printed at a high resolution of 400 lines (400dpi).

Processing 3! Processing for Dot Image

3-1! Smoothing (two pixels in the main scan direction in thisembodiment) is executed to take a moire countermeasure.

Processing 4! Processing for Halftone Image

4-1! Selection of smoothing (two pixels each in the main scan direction)or through processing can be enabled.

A circuit for executing the above processing operations will bedescribed below.

FIG. 21 is a block diagram of the character/image correction unit E.

The circuit shown in FIG. 21 comprises a selector 6e for selecting avideo input signal 111 or BkMj 112, an AND gate 6e' for generating asignal for controlling the selector, a block 16e for performing colorresidual removal processing (to be described later), an AND gate 16e forgenerating an enable signal of the removal processing, a multiplier 9e'for multiplying the signal GR 125 and a setup value 10e of an I/O port,a selector 11e for selecting a product 10e' or a setup value 7e of anI/O port in accordance with an output 12e of an I/O port 3, a multiplier15e for multiplying an output 13e from the selector 6e with an output14e from the selector 6e, an XOR gate 20e for logically XORing a product18e and an output 9e from an I/O port 4, an AND gate 22e, anadder/subtracter 24e, line memories 26e and 28e for delaying one-linedata, an edge emphasis block 30e, a smoothing block 31e, a selector 33efor selecting through data or smoothing data, a delay circuit 32e forperforming synchronization of a control signal SCRN 127 of the selector33e, a selector 42e for selecting an edge-emphasis or smoothing result,a delay circuit 36e for performing synchronization of a control signalMjAr 124 of the selector 42e, an OR gate 39e for logically ORing anoutput 37e from the delay circuit 36e and an output from an I/O port 8,an AND gate 41e, an inverter circuit 44e for outputting ahigh-resolution 400-line (dpi) signal ("L" output) to a characterjudgement unit, an AND gate 46e, an OR gate 48e, and a delay circuit 43efor performing synchronization between a video output 113 and a signalLCHG 49e. The character/image correction unit E is connected to the CPUbus 22 through an I/0 port 1e.

Three sections, i.e., 1! a section for performing color residual removalprocessing for removing a color signal remaining around an edge of ablack character portion, and performing subtraction of Y, M, and C dataof a black character judged portion at a predetermined ratio, andaddition of Bk data at a predetermined ratio, 2! a section for selectingedge emphasis for a character portion, smoothing for a dot judgedportion, and through data for other halftone images, and 3! a sectionfor setting the signal LCHG at "L" level (for performing printing at ahigh resolution of 400 dpi) will be described below.

1! Color Residual Removal Processing and Addition/Subtraction Processing

In this section, processing for a portion where both the signal GRBi 126as an achromatic color and the signal MjAr 124 as a character portionare active, i.e., for a black character edge portion and its surroundingportion, that is, removal of Y, M, and C components falling outside theblack character edge portion and black addition of an edge portion areexecuted.

A detailed operation will be described below.

This processing is executed only when a character portion is judged(MjAr 124="1"), a black character is determined (GRBi 126="1"), and aprinting mode is a color mode (DHi 122="0"). Therefore, this processingis not executed in an ND (black and white) mode (DHi="1") or for a colorcharacter (GRBi="0").

In an original scan mode of one of Y, M, and C data of recording colors,the video input 111 is selected by the selector 6e shown in FIG. 21 ("0"is set in an I/O-6 (5e)). The components 15e, 20e, 22e, and 17e generatedata to be subtracted from video data 8e.

For example, if "0" is set in the I/O-3 12e, the output data 13e fromthe selector 6e is multiplied with a value set in the I/O-7 17e andselected by the selector 11e by the multiplier 15e. In this case, thedata 18e 0 to 1 times the data 13e is generated. When "1" is set inregisters 9e and 25e, data of complementary number of 2 of the data 18eare generated by the components 17e, 20e, and 22e. Finally, data 8e and23e are added by the adder/subtracter 24e. In this case, however, sincethe data 23e is a complementary number of 2, subtraction of 17e-8e isactually performed, and a difference is output as 25e'.

When "1" is set in the I/O-3 12e, the selector 11e selects B data.

In this case, a product obtained by multiplying the multi-valueachromatic signal GR 125 (which has a larger value when it is closer toan achromatic color) generated by the character/image area separationcircuit I with a value set in the I/O-2 10e by the multiplier 9e is usedas a multiplicator of the data 13e. When this mode is used, coefficientscan be independently changed in units of colors Y, M, and C, and asubtraction amount can be changed according to achromaticity.

When a recording color Bk is scanned, the selector 6e selects the signalBkMj 112 ("1" is set in the I/O-6 5e). The components 15e, 20e, 22e, and17e generate data to be added to the video data 8e. A difference fromthe Y, M, or C scan mode is that "0" is set in the I/O-4 9e. Thus, since23e=8e and Ci=0, 17e+8e can be output as 25e'. The coefficient 14e isgenerated in the same manner as in the Y, M, or C scan mode. In a modewherein "1" is set in the I/O-3 12e, a coefficient is changed accordingto achromaticity. More specifically, when the achromaticity is large, anaddition amount becomes large; otherwise, it becomes small.

FIGS. 22A to 22D illustrate this addition/subtraction processing. FIGS.22A and 22C show an enlarged hatched portion of a black character Nillustrated in FIG. 22A-1. For video data Y, M, or C, a portion where acharacter signal portion is "1" is subtracted from the video data (FIG.22B), and for video data Bk, a portion where a character signal portionis "1" is added to the video signal portion (FIG. 22D). In FIGS. 22A to22D, 13e=18e, i.e., Y, M, or C data of a character portion is "0", andBk data is twice the video data.

With this processing, an outline portion of a black character is printedin an almost single black color. Portions indicated by marks "*" in FIG.22B of Y, M, or C data falling outside an outline signal remain asresidual color portions around a character, and present poor appearance.

In color residual removal processing, the residual color portions areremoved. In this processing, for a portion which falls within a range ofan expanded area of a character portion, and where the video data 13e issmaller than a value to be compared set by the CPU 20, i.e., a pixelhaving a possibility of a color residue outside a character portion, aminimum value of three or five pixels around the pixel is calculated.

This processing will be described below using the following circuit.

FIG. 23 shows a character area expansion circuit for expanding an areaof a character portion, and comprises DF/Fs 65e to 68e, AND gates 69e,71e, 73e, and 75e, and an OR gate 77e.

When "1" is set in all I/O ports 70e, 72e, 74e, and 76e, a signalexpanded by two pixels on both sides in the main scan direction isoutput as Sig2 18e if the signal MjAr 124="1". When "0" is set in theI/O ports 70e and 75e and "1" is set in the I/O ports ? 1e and 73e, asignal expanded by one pixel on both sides in the main scan direction isoutput as Sig2 18e. This switching signal is input to the AND gate 16e'shown in FIG. 21.

The color residual removal circuit 16e will be described below.

FIG. 24 is a circuit diagram of the color residual removal processingcircuit.

The circuit shown in FIG. 24 comprises a 3-pixel min select circuit 57efor selecting a minimum value of a total of three pixels, i.e., anobjective pixel and two adjacent pixels from the input signal 13e, a5-pixel min select circuit 58e for selecting a minimum value of a totalof five pixels, i.e., an objective pixel and two pixels on both sides ofthe objective pixel from the input signal 13e, a comparator 55e forcomparing the input signal 13e and an I/O-18 (54e), and outputting "1"when the I/O-18 54e is larger than the signal 13e, selectors 61e and62e, OR gates 53e and 53e', and a NAND gate 63e.

In this arrangement, the selector 60e selects the 3- or 5-pixel minimumvalue in accordance with the value of an I/O-19 from the CPU bus 22. The5-pixel minimum value can enhance a color residual removal effect. Theminimum values can be selected in manual selection by an operator or inautomatic selection by the CPU. The number of pixels for which theminimum value is to be calculated can be arbitrarily set.

The selector 62e selects an A input when the output from the NAND gate63e is "0", i.e., when the comparator 55e determines that the video data13e is smaller than the register value 54e and an input 17e' is "1";otherwise, it selects a B input (in this case, registers 52e and 64e are"1", and a register 52e' is "0").

When the B input is selected, through data is output as the data 8e.

An EXCON 50e can be used in place of the comparator 55e when a signalobtained by binarizing a luminance signal is input.

When the above-mentioned color residual removal processing is executed,color misregistration around a character can be removed, and a clearerimage can be obtained.

FIGS. 25A to 25F show a portion subjected to the above-mentioned twoprocessing operations. FIG. 25A shows a black character N, and FIG. 25Bshows an area which is judged as a character in Y, M, or C data asdensity data. That is, character judged portions (*2, *3, *6, and *7)become "0" by subtraction processing, and portions *1 and *4 arerespectively set to be *1←*0 and *4←*5 by the color residual removalprocessing, i.e., consequently become "0", thus obtaining a portionillustrated in FIG. 25C.

For Bk data shown in FIG. 25D, only addition processing is performed forcharacter judged portions (*8, *9, *10, and *11), thereby obtaining anoutput with a clear black outline.

For a color character, no modification is made, as shown in FIG. 25F.

2! Edge Emphasis or Smoothing Processing

In this section, processing for executing edge emphasis for a characterjudged portion, smoothing processing for a dot portion, and outputtingthrough data for other portions is executed.

Character portion→Since MjAr 124="1", a selector 42e selects an outputof an edge emphasis circuit 30e, which is generated based on signals onthree lines 25e, 27e, and 29e, and outputs the selected output. Notethat edge emphasis is executed based on a matrix and a formula shown InFIG. 26.

Dot portion→Since SCRN 35e="1" and MjAr 21e="0", a signal 27e issubjected to smoothing by a smoothing circuit 31e, and the smoothedsignal is selected by and output from a selector 33e and the selector42e. Note that smoothing is processing for, when an objective pixel isV_(N), as shown in FIG. 27, determining (V_(N) +V_(N+1))/2 as data ofV_(N), i.e., smoothing of main scan two pixels. Thus, moire noise whichmay be generated in a dot portion can be prevented.

Other portions→Other portions mean portions which are neither acharacter portion (character outline) nor a dot portion, i.e., halftoneportions. In this case, since both MjAr 124 and SCRN 35e="0", the data27e is directly output as the video output 113.

When a character is a color character, the above-mentioned twoprocessing operations are not performed even for a character judgedportion.

In this embodiment, the color residual removal processing is executed inonly the main scan direction. However, this processing may be executedin both the main and sub scan directions.

The types of edge emphasis filter are not to those described above.

Smoothing processing may also be executed in both the main and sub scandirections.

3! Processing for Outputting Character Portion

High Resolution of 400 Lines (dpi)

A signal LCHG is output from a gate 48e in synchronism with the videooutput 113. More specifically, an inverted signal of the signal MjAr 124is output in synchronism with a signal 43e. For a character portion,LCHG (200/400 switching signal)=0, and for other portions, LCHG="1".

A character judged portion, more specifically, a character outlineportion is printed by a laser beam printer at a high resolution of 400lines (dpi), and other portions are printed with multigradation of 200lines.

FIG. 25G shows a soft key screen of a liquid crystal touch panel 1109 ofthe operation unit 1000 for changing conditions of character/imageseparation processing. In this embodiment, five conditions can beselected by a soft key. The soft key has positions "low", "-2", "-1","normal", and "high" from the left-hand side of FIG. 25G. Thesepositions will be described in detail below.

Low!

The position "low" is used to avoid error judgement which inevitablyoccurs when an original from which line images end the like cannot bediscriminated is copied. At this position, a limiter value of thelimiter 123I shown in FIG. 15A is set to be an appropriate value.

As shown in FIG. 25H, at the position "normal", a limiter level ispresent in a bright portion of an original (limiter value=158 in thisembodiment). An output exceeding this limiter value is clipped to thelimiter value, as shown in FIG. 25I. When the position "low" isselected, the limiter level is set to be "0", as shown in FIG. 25J, andall the outputs are clipped to "0" (FIG. 25K). For this reason, anoutput binarized by the comparator 3 (126I) shown in FIG. 15A is all"1"s (or all "0"s), and no outline is extracted. As a result, no blackcharacter processing described above is executed for the read imagesignal. In this manner, the position "low" can prevent generation of anoutline signal, thereby preventing processing of a portion subjected toimage area separation.

-2! -1!

At the positions "-2" and "-1", error judgement of an original includingboth characters and images is made inconspicuous. In a normal originalcopying mode, the resolution switching signal LCHG is controlled so thatan outline portion of a black character of a character portion isprinted in single black color at a high resolution. At the positions"-2" and "-1", the resolution switching signal is controlled in the samemanner as for all other image portions, a black character is not printedin single black color, and a ratio of Y, M, and C data is increased asthe value of the position is decreased like "-1" and "-2". Thus, controlis made to decrease an image difference of processed images according toa judgement result.

This will be described below with reference to FIGS. 25L to 25P. FIG.25L shows read image data which becomes dark as a value is increased,and becomes light as a value is decreased. In image area separation ofthis embodiment, processing is performed for two pixels of an outlineportion, as shown in FIG. 25L. When a soft lever displayed on the touchpanel is at the positions normal! and high!, a ratio of an outlineportion is increased, so that for Y, M, and C data, a Y, M, or C toneris not printed on two pixels of the outline portion of a black characterand a line, as shown in FIG. 25M, and for Bk data, a black line orcharacter can look sharp, as shown in FIG. 25N. In the -1! and -2!modes, toners of Y, M, and C data can be slightly left on an outlineportion, as shown in FIG. 250, and a toner of Bk data is decreased, asshown in FIG. 25P.

Normal!

At the position "normal", the above-mentioned processing is executed.

High!

At the position "high", parameters are set so no error judgement occursfor a character, and a thin or light character is printed in singleblack color. More specifically, when the limiter value of the limiter 3(123I in FIG. 15A) of the outline signal is increased, an outline signalof a highlight portion can be extracted.

In this manner, image area separation conditions and processing based onseparation are changed according to an image to be read, so that errorjudgement can be avoided or made inconspicuous.

Since the limiter value can be easily changed by the CPU 20, a circuitarrangement will not be complicated.

The number of levels of black character processing need not always befive. When the number of levels is increased, processing matching withan original image can be selected.

<Relationship With Mode Selection>

Processing according to selection of an output color mode such as afour-color mode, a three-color mode, a single-color mode, or the likewill be described below.

A digital copying machine has a function of copying an image in a colordifferent from an original color, e.g., a function of copying afull-color original in monocolor. In a portion subjected to image areaseparation described above, a color balance is changed to meet arequirement of a clear character. For this reason, when theabove-mentioned processing is performed for an input image after animage area is separated, an output image in considerably degraded.

In this embodiment, in order to provide an image processing apparatuswhich is free from image degradation caused by a difference in outputcolor mode, conditions of the image area judgement means or processingmeans according to judgement are changed according to an output colormode.

When a monochromatic signal described in the masking unit is selected,or when a three-color mode for forming an image using only Y, M, and Ctoners is selected, input image processing by the image area separationprocessing of this embodiment is not performed.

More specifically, processing is performed as follows.

As shown in FIG. 25H, in a four-color mode for recording an image infour colors, e.g., Y, M, C, and Bk, a limiter level is present in abright portion of an original (limiter value=158 in this embodiment). Anoutput exceeding this limiter value is clipped to the limiter value, asshown in FIG. 25I. In the three-color mode for recording an image inthree colors, i.e., Y, M, and C, when the limiter level is set to be 0,as shown in FIG. 25J, all the output signals are clipped to 0. For thisreason, an output binarized by the comparator 3 (126I) in FIG. 15Abecomes all "1" s or (all "0"s), no outline is extracted, and noprocessing is executed to a read image signal. In this manner, in thethree-color mode, generation of an outline signal is prevented, so thatprocessing of a portion where an image area is separated is inhibited.

In the single-color mode, processing for extracting a character signalis inhibited as in the three-color mode.

In this embodiment, a color copying machine which has a judgement meansfor judging based on input image information whether the input imageinformation is image or character information, and a processing meansfor processing the input information in accordance with the judgementresult, has a color mode different from a normal copying mode, andvaries the processing according to the judgement result in the colormode different from the normal copying mode. Thus, processing can besimplified, and error judgement can be prevented.

<Relationship Between Lamp Light Amount and Control>

A digital color copying machine is required to have background coloromission processing performed in a conventional analog copying machine.A system of omitting a background color of a newspaper by changing alamp light amount is proposed.

When a light amount of a light source is changed, however, the level oflight reflected by an original also changes, and error judgement tendsto occur in a separation system which judges characters or imagesaccording to a contrast or color of a read image signal.

In this embodiment, the character/image judgement conditions are changedaccording to an original read light amount, thereby eliminating errorjudgement in character/image judgement caused by a change in lightamount.

Lamp light amount adjustment will be described below. FIG. 25Q shows theflow of lamp light amount adjustment. In a prescan mode of detecting aposition, size, and the like of an original, data of 50 points in themain scan direction and 30 lines at equal intervals in the sub scandirection, i.e., data of a total of 1,500 points are read, and thenumber of data of an original is counted (S1). A maximum value of thedata is detected (S2), and the number of data points having valueswithin 85% to 100% of the maximum value is counted (S3). In this case,only when the maximum value is equal to or larger than 60 H (84) andpoints 1/4 the total have values 85% to 100% of the maximum value (S5),light amount adjustment is performed (S7). A light amount is set so thatthe maximum value becomes FF_(H) : ##EQU5##

The value obtained by the above equation is set as a lamp light amountset value (S6).

When the maximum value of data is less than 60 H, or when points lessthan 1/4 the total of points have values 85% to 100% of the maximumvalue, lamp light amount adjustment is not performed.

When the light amount adjustment is performed, values larger than thenormal one are set in the offset register 2 (119I) and the offsetregister 3 (124I). When the lamp light amount is increased, the dynamicrange of a read original density is narrowed. Thus, a noise component ofan original is undesirably detected, error judgement in dot detectionand error detection in outline extraction occur. In order to preventerror detection caused by the noise component, the offset values areincreased only when the light amount adjustment is performed.

In this manner, according to this embodiment, in a copying machinehaving an original reading means for reading an image by opticalscanning, a light amount adjusting means for adjusting a light amount ofa read light source in correspondence with a density of an original tobe read, a judgement means for judging that the read image informationis halftone or character information, and a processing means forprocessing the input information on the basis of the judgement result,the judgement condition is changed when the light amount adjustment isperformed.

In this embodiment, lamp light amount control is performed under a givencondition. However, lamp light amount control may be executed in all thecases.

Sampling data in a prescan mode can be increased/decreased. A thresholdvalue for determining whether or not light amount adjustment is to beexecuted can be changed.

A condition for judging character and image areas may be selected from aplurality of stages according to light amount adjustment.

<Character/Image Synthesizing Circuit>

The character/image synthesizing circuit F will be described below. FIG.28A is a block diagram of a process and modulation circuit of a binaryimage signal. Color image data 138 input from an image data input unitis input to a V input of a 3 to 1 selector 45f. An A input of the 3 to 1selector 45f receives a A_(n) of a lower-bit portion (A_(n), B_(n)) 555fread out from a memory 43f, and a B input thereof receives B_(n) afterthe lower-bit portion 555f is latched by a latch 44f in response to asignal VCLK 117. Therefore, one of the V, A, and B inputs appears at anoutput Y of the selector 45f on the basis of select inputs X₀, X₁, J1,and J2 (114). Data X_(n) consists of upper 2 bits of data in the memory,and serves as a mode signal for determining a process or modulationmode. A signal 139 is a code signal output from the area signalgeneration circuit, is switched in synchronism with the signal VCLK 117under the control of the CPU 20 shown in FIG. 2, and is input to thememory 43f as an address signal. More specifically, when (X₁₀, A₁₀,B₁₀)=(01, A₁₀, B₁₀) is written in advance at an address "10" of thememory 43f, if "10" is given between points P and Q of the code signal139 and "0" is given between points Q and R in synchronism with scanningof a main scanning line 1, data X_(n) =(0, 1) is read out between P andQ, and at the same time, data (A₁₀, B₁₀) is latched in (A_(n), B_(n)).FIG. 28C shows a truth table of the 3 to 1 selector 45f. As shown inFIG. 28C, (X₁, X₀)=(0, 1) corresponds to a case (B). If J1="1", the Ainput is output to the Y output, and, hence, the constant A₁₀ appears atthe Y output. On the other hand, if J1="0", the V input is output to theY output, and hence, input color image data is directly output as theoutput 114. In this manner, so-called butt-to-line character synthesisof a character portion having a value (A₁₀) to a color image of an appleshown in, e.g., FIG. 29B can be realized. Similarly, when (X₁, X₀)=(1,0) and a signal J1 in FIG. 29C is input to a binary input, FIFO memories47f to 49f and a circuit 46f (shown in detail in FIG. 28B) generate asignal J2 in FIG. 29C. As a result, a character with a frame is outputto an image of an apple, as shown in FIG. 29C, according to the truthtable of FIG. 28C (outline or open type). Similarly, in FIG. 29D, arectangular area in an apple is output at a density of (B_(n)), and acharacter in the image of the apple is output at a density of (A_(n))FIG. 29A shows a case of (X₁, X₀)=(0, 0), i.e., no processing isperformed for a binary signal regardless of changes in J1 and J2.

A signal having an expanded width input to the input J2 undergoesexpansion corresponding to 3×3 pixels according to FIG. 28B. When ahardware circuit is added, the signal can be easily expanded more.

An FHi signal 121 input to the FIFO memory 47f is a non-rectangular areasignal stored in the 100-dpi binary memory L shown in FIG. 2. When thisFHi signal 121 is used, the above-mentioned various processing modes arerealized.

The outputs C0 and C1 (366, 367) output from the I/O port 501 (FIG. 2)in correspondence with an output color to be printed (Y, M, C, Bk) areinput to lower 2 bits of the address of the memory 43f, and hence, arechanged like "0, 0", "0, 1", "1, 0", and "1, 1" in correspondence withoutputs Y, M, C, and Bk. Therefore, in, e.g., a yellow (Y) output mode,addresses "0", "4", "8", "12", "16", . . . , are selected; in a magenta(M) output mode, addresses "1", "5", "9", "13", "17", . . . , areselected; in a cyan (C) output mode, addresses "2", "6", "10", "14","18", . . . , are selected; and in a black (Bk) output mode, "3", "7","11", "15", "19", . . . , are selected. Thus, upon operationinstructions on the operation panel (to be described later), forexample, X1 to X4="1, 1" (A1, A2, A3, A4)=(α1, α2, α3, α4) and (B1, B2,B3, B4)=(β1, β2, β3, β4) are written at addresses corresponding to thearea code signal 139 for determining an area and corresponding memoryaddresses in the area. For example, if the signal J1 is changed, asshown in FIG. 29D, a color is determined by a mixture of (Y, M, C,Bk)=(α1, α2, α3, α4) during a "Lo" period of J1, and a color isdetermined by a mixture of (Y, M, C, Bk)=(β1, β2, β3, β4) during a "Hi"period of J1. More specifically, an output color can be arbitrarilydetermined by the memory content. On the operation panel (to bedescribed later), each of Y, M, C, and Bk is adjusted or set in units of%. Since each gradation level has 8 bits, its value can be varied withina range of 00 to 255. Therefore, a variation of 1% corresponds to 2.55in digital value. If set values are (Y, M, C, Bk)=(y %, m %, c %, k %),values to be set (i.e., values written in the memory) are respectively(2.55y, 2.55m, 2.55c, 2.55k). In practice, rounded values are written inthe predetermined memory. When densities are adjusted in units of % byan adjustment mechanism, values obtained by adding (darkening) orsubtracting (lightening) 2.55Δ with respect to a variation of Δ% can bewritten in the memory.

In this manner, according to this embodiment, output colors Y, M, C, andBk can be designated in units of %, and operability of color designationcan be improved.

In the truth table of FIG. 28C, a column of i corresponds to an I/Otable of the character/image gradation/resolution switching signal LCHG149. When the A or B input is output to the output Y according to theinputs X₁, X₀, J1, and J2, i="0"; when the input V is output to theoutput Y, the input is directly output. The signal LCHG 149 is a signalfor switching an output printing density. When LCHG="0", printing ismade at, e.g., a high resolution of 400 dpi; when LCHG="1", printing isperformed with multigradation of 200 dpi. Therefore, if LCHG="0" whenthe input A or B is selected, an inner area of a synthesized characteris printed at 400 dpi, and an area other than the character is printedat 200 dpi. As a result, the character can be output sharp at a highresolution, and a halftone portion can be smoothly output withmultigradation. For this purpose, the signal LCHG 149 is output from thecharacter/image correction circuit E on the basis of the signal MjAr asthe output from the character/image area separation circuit I, asdescribed above.

<Image Process and Edit Circuit>

An image signal 115 subjected to color balance adjustment in the circuitP (FIG. 2) and a gradation/resolution switching signal 141 are input tothe image process and edit circuit G. FIG. 30 is a schematic view of theimage process and edit circuit G.

The input image signal 115 and gradation/resolution switching signalLCHG 141 are input to a texture processing unit 101g. The textureprocessing unit can be roughly constituted by a texture memory 103g forstoring a texture pattern, a memory RD,WR address control unit 104g forcontrolling the memory 103g, and a calculation circuit 105g forperforming modulation processing of input image data on the basis of thestored pattern. Image data processed by the texture processing unit 101gis then input to a zoom, mosaic, taper processing unit 102g. The zoom,mosaic, taper processing unit comprises double buffer memories 105g and106g, and a processing/control unit 107g, and various processingoperations are independently controlled by the CPU 20. The textureprocessing unit 101g, and the zoom, mosaic, taper processing unit 102can perform texture processing and mosaic processing of independentareas in accordance with processing enable signals GHi1 (119) and GHi2(149) sent from the switch circuit N.

The gradation/resolution switching signal LCHG 141 input together withthe image data 115 is processed while its phase is matched with an imagesignal in various edit processing operations. The image process and editcircuit G will be described in detail below.

<Texture Processing Unit>

In the texture processing, a pattern written in the memory is cyclicallyread out to modulate video data. For example, an image shown in, e.g.,FIG. 31A is modulated by a pattern shown in FIG. 31B, thereby generatingan output image, as shown in FIG. 31C.

FIG. 32 is a circuit diagram for explaining the texture processing unit.A write section of modulation data 218g of the texture memory 113g and acalculation section (texture processing) of data 216g from the texturememory 113g and image data 215g will be described below in turn.

Data Write Section of Texture Memory 113g!

In a data write mode, the color correction circuit D for performingmasking, UCR, black extraction, and the like outputs (Y+M+C)/3, and thedata is input from a video input 201g. This data is selected by aselector 202g. A selector 208g selects data 220g, and inputs theselected data to a terminal WE of the memory 113g and an enable signalterminal of a driver 203g. A memory address is generated by a verticalcounter 212g which is incremented in synchronism with a horizontal syncsignal HSYNC, and a horizontal counter 211g which is incremented insynchronism with an image clock VCK. When a selector 210g selects its Binput, the address is input to an address terminal of the memory 113g.In this manner, a density pattern of an input image is written in thememory 113g. As this pattern, a position on an original is designated byan input device, e.g., a digitizer 58, and image data obtained byreading the designated portion is written in the memory 113g.

Data Write Access by CPU!

CPU data is selected by the selector 202g. On the other hand, theselector 208g selects its A input, and the selected input is input tothe terminal WE of the memory 113g and the enable signal terminal of thedriver 203g. The memory address is input to the address terminal of thememory 113g when the selector 210g selects its A input. In this manner,an arbitrary density pattern is written in the memory.

Calculation Section of Data 216g of Texture Memory 113g and Image Data215g!

This calculation is realized by a calculator 215g. In this embodiment,the calculator comprises a multiplier. Only when an enable signal 128gis enabled, a calculation of the data 216g and 201g is executed; when itis disabled, the input 201g goes through the calculator.

300g and 301g respectively designate XOR and OR gates. When "1" and "0"are respectively set in registers 304g and 305g as portions forgenerating an enable signal using an MJ signal 308g, i.e., a charactersynthesizing signal, texture processing is performed for a portionexcluding a character synthesizing signal. On the other hand, when "0"and "0" are respectively set in the registers 304g and 305g, the textureprocessing is performed for a portion including the charactersynthesizing signal.

A gate 302g serves to generate an enable signal using a GHi1 signal307g, i.e., a non-rectangular area signal. When "0" is set in theregister 306g, the texture processing is performed for only a portionwhere the GHi1 signal is enabled. In this case, if the enable signal 128is kept enabled, non-rectangular texture processing is performedregardless of a non-rectangular area signal, i.e., in synchronism withHSYNC. If the signal GHi1 and the enable signal 128 are synchronized,texture processing synchronous with a non-rectangular area signal isexecuted. If a 31b-bit signal is used as the signal GHi1, textureprocessing can be executed for only a specific color.

The LCGH_(IN) signal 141g is a gradation/resolution switching signal, isdelayed by the calculator 215g, and is output as a signal LCHG_(OUT)350g. In this manner, in the texture processing unit, thegradation/resolution switching signal LCHG 141 is also subjected topredetermined delay processing in correspondence with an image subjectedto the texture processing.

<Mosaic, Zoom, Taper Processing Unit>

The operation of the mosaic, zoom, taper processing unit 102g of theimage process and edit circuit G will be briefly described below withreference to FIG. 33.

The image data 126g and the LCHG signal 350g input to the mosaic, zoom,taper processing unit 102g is first input to a mosaic processing unit401g, In the mosaic processing unit 401g, the input data are subjectedto determination of the presence/absence of mosaic processing and themain scan size of a mosaic pattern, synthesis of a character, and thelike in accordance with the MJ signal 145 output from the charactersynthesizing circuit F, the area signal GHi2 (149) output from theswitch circuit N, and a mosaic clock HCLK from a mosaic processingcontrol unit 402g. Thereafter, the processed data are input to a 1 to 2selector 403g, The area signal GEi2 is generated on the basis ofnon-rectangular area information stored in the binary memory L (FIG. 2).In response to this signal, mosaic processing of a non-rectangular areais allowed. Note that the main scan size of the mosaic processing can bevaried by controlling the mosaic clock HCLK. Control of the mosaic clockMCLK will be described in detail later.

The 1 to 2 selector 403g outputs the input image signal and the LCHGsignal to one of terminals Y1 and Y2 in accordance with a line memoryselect signal LMSEL obtained by frequency-dividing a signal HSYNC 118 bya D flip-flop 406g.

The outputs from the terminal Y1 of the 1 to 2 selector 403g areconnected to a line memory A 404g and an A input of a 2 to 1 selector407g. The outputs from the terminal Y2 are connected to a line memory B405g and a B input of the 2 to 1 selector 407g. When an image is sentfrom the selector 403g to the line memory A, the line memory A 404g isset in a write mode, and the line memory B 405g is set in a read mode.Similarly, when an image is sent from the selector 403g to the linememory B 405g, the line memory B is set in the write mode, and the linememory A 404g is set in the read mode. In this manner, image dataalternately read out from the line memories A 404g and B 405g are outputas continuous image data while being switched by the 2 to 1 selector207g in response to an inverted signal of the LMSEL signal output fromthe D flip-flop processing by an enlargement processing unit 414g, and406g. The output image signal from the 2 to 1 selector 407g is subjectedto predetermined enlargement processing by an enlargement processingunit 414g, and the processed signal is then output.

Read/write control of these memories will be described below. In thewrite and read modes, addresses supplied to the line memories A 404g andB405g are incremented/decremented by up/down counters 409g and 410g insynchronism with the signal HSYNC as a reference of one scan period, andan image CLK. The address counters (409g and 410g) are controlled by acounter enable signal output from the line memory address control unit413g, and control signals WENB and RENB, generated from a zoom controlunit 415g, for respectively controlling write and read addresses. Thesecontrolled address signals are respectively input to the 2 to 1selectors 407g and 408g. The 2 to 1 selectors 407g and 408g supply aread address to the line memory A 404g and a write address to the linememory B 405g in response to the above-mentioned line memory selectsignal LMSEL when the line memory A 404g is in the read mode. When theline memory A 404g is in the write mode, an operation opposite to thatdescribed above is executed. Memory write pulses WEA and WEB to the linememories A and B are output from the zoom control unit 415g. The memorywrite pulses WEA and WEB are controlled when an input image is to bereduced and when an input image is subjected to mosaic processing by amosaic length control signal MOZWE in the sub scan direction, which isoutput from the mosaic processing control unit 402g. A detaileddescription of these operations will be made below.

<Mosaic Processing>

Mosaic processing is basically realized by repetitively outputting oneimage data. The mosaic processing operation will be described below withreference to FIG. 34.

The mosaic processing control unit 402g independently performs main andsub scan mosaic processing operations. The CPU sets variablescorresponding to a desired mosaic size in latches 501g (main scan) and502g (sub scan) connected to the CPU bus. The main scan mosaicprocessing is executed by continuously writing the same data at aplurality of addresses of the line memory. The sub scan mosaicprocessing is executed by thinning data to be written in the line memoryevery predetermined lines in a mosaic processing area.

(Main Scan Mosaic Processing)

A variable corresponding to a main scan mosaic width is set by the CPUin the latch 501g. The latch 501g is connected to a main scan mosaicwidth control counter 504g, and loads a set value in response to anHSYNC signal and a ripple carry of the counter 504g. The counter 504gloads a value set in the latch 501g in response to each HSYNC signal.When the counter 504g counts a predetermined value, it outputs a ripplecarry to a NOR gate 502g and an AND gate 509g. A mosaic clock MCLK fromthe AND gate 509g is obtained by thinning the image clock CLK by theripple carry from the counter 504g. Only when the ripple carry isgenerated, the clock MCLK is output. The clock MCLK is then input to themosaic processing unit 401g.

The mosaic processing unit 401g comprises two D flip-flops 510g and511g, a selector 512g, an AND gate 514g, and an inverter 513g. Theflip-flops 510g and 511g are connected to the gradation/resolutionswitching signal LCHG in addition to an image signal, and hold the inputimage data and the LCHG signal in response to the image clock CLK (510g)and the mosaic processing clock MCLK (511g), respectively. Morespecifically, the gradation/resolution switching signal LCHGcorresponding to one pixel is held in the flip-flops 510g and 511g in aphase-matched state during CLK and MCLK periods. The held image signaland LCHG signal are input to the 2 to 1 selector 512g. The selector 512gswitches its output in accordance with a mosaic area signal GHi2, and abinary character signal Mj. The selector 512g performs an operationshown in the truth table below using the AND gate 514g and the inverter513g.

    ______________________________________                                        GHi2             Mj    Y                                                      ______________________________________                                        0                0     A                                                      0                1     A                                                      1                0     B                                                      1                1     A                                                      ______________________________________                                    

When the mosaic area signal GHi2 149 is "0", the selector 512g outputsthe signals from the flip-flop 510g regardless of the Mj signal. Whenthe GHi2 signal 149 is "1" and the MJ signal is "0", the selector 512goutputs the signals from the flip-flop 511g which is controlled by themosaic clock MCLK. When the Mj signal is "1", the selector 512g outputsthe signals from the flip-flop 510g. With this control, a portion of animage subjected to main scan mosaic processing can be output withoutbeing processed. More specifically, no mosaic processing is performedfor a character synthesized in an image by the character synthesizingcircuit F (FIG. 2), and only an image can be subjected to mosaicprocessing. The outputs from the selector 512g are input to the 2 to 1selector 403g shown in FIG. 33. In this manner, the main scan mosaicprocessing is performed.

(Sub Scan Mosaic Processing)

The sub scan mosaic processing is controlled by the latch 502g connectedto the CPU bus, a counter 505g, and a NOR gate 503g as in the main scanmosaic control. The sub scan mosaic width control counter 505g,generates a ripple carry pulse in synchronism with an ITOP signal 144and by counting an HSYNC signal 118. The ripple carry pulse is input toan OR gate 508g together with an inverted signal GHi2 of the mosaic areasignal GHi2 149, and the character signal Mj. The sub scan mosaiccontrol signal MOZWE is subjected to control shown in the truth tablebelow.

    ______________________________________                                        GHi2     Mj            RC    MOZWE                                            ______________________________________                                        0        X             X     1                                                1        0             0     0                                                1        0             1     1                                                1        1             X     1                                                ______________________________________                                    

The MOZWE signal output in these combinations is input to the zoomcontrol unit 415g, and controls a write pulse generated by a line memorywrite pulse generation circuit (not shown) in a NAND gate 515g. Thewrite pulse generation circuit can vary an output clock rate of, e.g., arate multiplier normally used in zoom control. Since this circuit fallsoutside the scope of the present invention, a detailed descriptionthereof will be omitted in this embodiment. A WR pulse controlled by theMOZWE signal is output alternately as the pulses WEA and WEB from the 1to 2 selector in response to the switching signal LMSEL which switchespulses in response to the HSYNC signal 118. With the above-mentionedcontrol, even when the mosaic area signal GHi2 149 is "1", if the Mjsignal goes to "1" level, write access of the memory is performed. Thus,a portion of a sub-scan mosaic-processed image can be output withoutbeing processed. FIG. 35A shows a distribution of density values inunits of pixels for a given recording color when mosaic processing isactually executed. In the mosaic processing shown in FIG. 35A, pixels ina 3×3 pixel block are used as typical pixel values. In this processing,a character "A", i.e., hatched pixels in FIG. 35A are not subjected tomosaic processing based on the character signal Mj. More specifically,when a synthesized character overlaps a mosaic processing area, thecharacter has a priority over the mosaic processing. Therefore, when themosaic processing is performed, an image can be formed, so that acharacter can be read. A mosaic area is not limited to a rectangulararea. For example, mosaic processing can be executed to anon-rectangular area.

(Inclination and Taper Processing)

Inclination processing will be described below with reference to FIGS.33 and 36.

FIG. 36 shows the internal arrangement of the line memory addresscontrol unit 413g shown in FIG. 33. The line memory address control unit413g controls enable signals of the write and read counters 409g and410g. The control unit 413g controls the counters to determine a portionof one main scan line to be written in or read out from the line memory,thereby achieving, e.g., shift and inclination of a character. An enablecontrol signal generation circuit will be described below with referenceto FIG. 36.

A counter output of a counter 701g is reset to "0" in response to theHSYNC signal, and the counter 701g then counts the image clocks CLK 117.The output Q of the counter 701g is input to comparators 706g, 708g,709g, and 710g. The A input sides of the comparators excluding thecomparator 709g are independent latches (not shown) connected to the CPUbus 22. When arbitrarily set values and the output from the counter 701gcoincide with each other, these comparators output pulses. The output ofthe comparator 706g is connected to the J input of the J-K flip-flop708g, and the output from the comparator 707g is connected to the Kinput. The J-K flip-flop 708g outputs "1" from when the comparator 706goutputs a pulse until the comparator 707g outputs a pulse. This outputis used as a write address counter control signal, and the write addresscounter is enable during only a "1" period to generate an address to theline memory. A read address counter control signal similarly controlsthe read address counter. The A input of the comparator 709g isconnected to a selector 703g to vary an input value to the comparatordepending on a case wherein inclination processing may or may not beperformed. When the inclination processing is not performed, a value setin a latch (not shown) connected to the CPU bus 22 is input to the Ainput of the selector 703g, and the A input is output from the selector703g in response to a select signal output from a latch (not shown). Thefollowing operations are the same as those of the comparators 706g and707g. When the inclination processing is performed, a value input to theA input of the selector 703g is also input to a selector 702g as apreset value. When the select signals input to the selectors 702g and703g select their B inputs, the output from the selector 702g is addedto a value set in a latch (not shown) by an adder 704g. The sumrepresents a change amount per line based on an inclination angle, andif a required angle is represented by θ, the change amount can be givenby tanθ. The sum is input to a flip-flop 705g which receives the HSYNCsignal 118 as a clock, and is held by the flip-flop 705g for one mainscan period. The output from the flip-flop 705g is connected to the Binputs of the selectors 702g and 703g. When this addition is repeated,the output from the selector to the comparator 709g changes at apredetermined rate for each scan period, so that the start of the readaddress counter can be varied from the HSYNC signal at a predeterminerate. Thus, data are read out from the line memories A 404g and B 405gat timings shifted from the HSYNC signal, thus allowing the inclinationprocessing. The above-mentioned change amount can be either a positiveor negative value. When the change amount is positive, the read timingis shifted in a direction to separate from the HSYNC signal; when it isnegative, the read timing is shifted in a direction to be closer to theHSYNC signal. The select signals of the selectors 702g and 703g arechanged in synchronism with the HSYNC signal, so that a portion of animage can be converted to an inclined character.

As an enlargement processing methods, 0th, linear, SINC interpolationmethods, and the like are known. However, since this operation is notincorporated in the present invention, a detailed description thereofwill be omitted. When a main scan magnification is changed insynchronism with the HSYNC signal for each scan line while theinclination processing is being executed, taper processing can berealized.

The above-mentioned processing operations can also be performed for anon-rectangular area in accordance with the non-rectangular area signalGHi as in the mosaic processing and texture processing.

In these processing operations, the input gradation/resolution switchingsignal is processed while its phase is matched with an image signal.More specifically, the switching signal LCHG 142 is similarly processedas an image signal is processed in the zoom, inclination, taperprocessing modes, and the like. The output image data 114 and the outputgradation/resolution switching signal LCHG 142 are output to the edgeemphasis circuit.

FIGS. 35B and 35C show the principle of the above-mentioned inclinationprocessing and taper processing.

<Outline Processing Unit>

FIGS. 35D and 35F are views for explaining outline processing. In thisembodiment, as shown in FIG. 35D, an inside signal of a character orimage (an inner broken line in (I) of FIG. 35D, 103Q in (II) thereof)and an outside signal (an outer broken line in (I) of FIG. 35D and 102Qin (II) thereof) are generated, and are logically ANDed, therebyextracting an outline. In the timing chart ((II) of FIG. 35D), 101Qdesignates a signal obtained by binarizing a multi-value original signalby a predetermined threshold value. The signal 101Q represents aboundary portion between an original image (hatched portion) and abackground shown in (I) of FIG. 35D. Contrary to this, 102Q designates asignal obtained by expanding a "Hi" portion of the signal 101Q to fattena character portion (fattened signal), and 103Q designates a signal byshrinking the "Hi" portion of the signal 101Q to thin a characterportion (thinned signal), and than inverting the obtained signal. 104Qdesignates an AND product of the signals 102Q and 103Q, i.e., anextracted outline signal. A hatched portion of the signal 104Qrepresents that a wider outline can be extracted. That is, a fatteningwidth is further increased in the signal 102Q, and a shrinking width isfurther increased in the signal 103Q, so that an outline having adifferent width can be extracted. In other words, the width of theoutline can be changed. FIG. 35F is a circuit diagram for realizing theoutline processing described with reference to FIG. 35D. This circuit isarranged in the image process and edit circuit G shown in FIG. 2. Inputmulti-value image data 138 is compared with a predetermined thresholdvalue 116q by a comparator 2q, thereby generating a binary signal 101q.The threshold value 116q is an output from a data selector 3q, i.e., asignal selected by and output from the selector 3q in correspondencewith a certain color in accordance with outputs 110q to 113q from valuesr1, r2, r3, and r4 set in a register group 4q in units of printingcolors, i.e., yellow, magenta, cyan, and black by the CPU (not shown). Abinarization threshold value can be varied in units of colors inresponse to signals 114q and 115q which are switched in units of colorsby the CPU (not shown), thereby varying a color outline effect. The dataselector 3q respectively selects A, B, C, and D inputs when, forexample, (114q, 115q)=(0, 0), (0, 1), (1, 0), and (1, 1), and theseinputs respectively correspond to yellow, magenta, cyan, and blackthreshold values. The binary signal 101q is stored in line buffers 5q to8q for five lines, and is output to a next fattening circuit 150q and anext thinning circuit 151q. The circuit 150q generates a signal 102q.When a total of 25 (or 9) pixels of a 5×5 (or 3×3) small pixel blockinclude at least one "1" pixel, the circuit 150q determines the value ofa central pixel to be "1". More specifically, for an original image(hatched portion) shown in (I) of FIG. 35D, an outside signal O of twopixels (or one pixel) is generated. Similarly, the circuit 151qgenerates a signal 103q. When a total of 25 (or 9) pixels of a 5×5 (or3×3) small pixel block include at least one "0" pixel, the circuit 151qdetermines the value of a central pixel to be "0". That is, an insidesignal I of two pixels (or one pixel) is formed for (I) of FIG. 35D.Therefore, as has been described with reference to (II) of FIG. 35D, thesignals 102q and 103q are logically ANDed by an AND gate 41q, thusforming an outline signal 104q. As can be seen from a circuit operation,signals 110q and 111q are select signals for selecting the 3×3 or 5×5small pixel block. When the 3×3 pixel block is selected, (110q,111q)=(0, 1). An outline width in this case corresponds to two pixelssince a fattening width is one pixel and a thinning width is one pixel.When the 5×5 pixel block is selected, (110q, 111q)=(1, 1), and theoutline width corresponds to four pixels. These selections arecontrolled by an I/O port connected to the CPU (not shown), so that anoperator can switch the pixel block according to a required effect.

In FIG. 35F, a selector 45q can switch whether the original signal 138is directly output or the extracted outline is output. The selector 45qselects one of the A and B inputs based on an output from a selector45q'. The selector 45q' outputs one of an inverted signal of the outlinesignal 104q and a signal ESDL output from the I/O port connected to theCPU (not shown) as a select signal of the selector 45q. In this case,the CPU inputs a select signal SEL to the selector 45q'.

A selector 44q selects one of fixed values r5 and r6, which are set inregisters 42q and 43q by the CPU, in accordance with the outline signal104q. All the selectors 44q, 45q, and 45q' select the A inputs when aswitching terminal S=0; they select the B inputs when S=1.

When "1" is input to the switching terminal of the selector 45q', the Binput terminal is selected, and the selector 45q is switched by thesignal ESDL output from the I/O port connected to the CPU (not shown).When ESDL="0", the A input of the selector 45q is selected, and normalcopy mode is set; when ESDL="1", the B input is selected, and an outlineoutput mode is set. The registers 42q and 43q are set up with the fixedvalues r5 and r6 by the CPU (not shown). When the outline output 104q is"0" in the outline output mode, the fixed value r5 is output; when104q="1", the fixed value r6 is output. More specifically, for example,if r5=00_(H) and r6=FF_(H), the outline portion is FF_(H), i.e., black,and other portions are 00_(H), i.e., white, thus forming an outlineimage, as shown in FIG. 35E. Since the values r5 and r6 areprogrammable, they can be changed in units of colors to obtain differenteffects. That is, FF_(H) and 00_(H) need not always be set, and twodifferent levels, e.g., FF_(H) and 88_(H) may be set.

When "0" is set in the switching terminal S of the selector 45q', the Ainput is selected, and an inverted signal of the outline signal 104q isinput to the switching terminal S of the selector 45q. The selector 45qoutputs original data at the A input for an outline portion, and outputs00_(H), i.e., white as the fixed value at the B input selected by theselector 44q for portions excluding the outline portion. In this manner,the outline portion can be subjected to processing not by the fixedvalue but by multi-value original data for each of Y, M, C, and K.

According to this embodiment, a mode of outputting a binary outlineimage output (multi-color outline processing mode) and a mode ofoutputting a multi-value outline image output (full-color outlineprocessing mode) can be arbitrarily selected by an operator for each ofY, M, C, and K.

For the threshold values of outline extraction, the values r1, r2, r3,and r4 are set in the registers 4q, so that different values can be setfor Y, M, C, and K, respectively. These values can also be rewritten bythe CPU.

When a matrix size is selected, an outline width can be changed, thusobtaining a different outline image.

The outline extraction matrix size is not limited to the 5×5 and 3×3sizes described above, and can be desirably changed byincreasing/decreasing the numbers of line memories and gates.

The outline processing circuit Q shown in FIG. 35F is arranged in theimage process and edit circuit G shown in FIG. 2. This image process andedit circuit G also includes the texture processing unit 101g and thezoom, mosaic, taper processing unit 102g. Since these units areconnected in series with each other, their processing operations can bedesirably combined upon operation of the operation unit 1000 (to bedescribed later). The order of these processing modes can be desirablyset by a combination of a parallel circuit of the processing units andselectors.

In this embodiment, each color component input to the outline processingcircuit Q is binarized to obtain an outline signal for each colorcomponent, and an outline image is output in color corresponding to thecolor component. However, the present invention is not limited to thismethod. For example, an ND image signal can be generated based on a readsignal R (red), G (green), or B (blue), an outline can be extractedbased on these signals, and original multi-value data, predeterminedbinary data or the like in units of recording colors can be substitutedin the extracted outline portion to form an outline image. In this case,the ND image signal can also be generated based on one of the R, G, andB signals. In particular, since the G signal has characteristics closestto those of the neutral density signal (ND image signal), this G signalcan be directly used as the ND signal in terms of a circuit arrangement.

A Y signal (luminance signal) of an NTSC system may also be used.

<Non-rectangular Area Memory>

A means for storing a non-rectangular area designated in the presentinvention will be described below.

In conventional designated area edit processing, as a designated area, arectangular area, only a non-rectangular area with the limited number ofinput points (FIG. 37F), or a combination of the rectangular andnon-rectangular areas (FIG. 37G) are available. Therefore, the followingdrawbacks are posed.

That is, as shown in FIG. 37H, since red letters "Fuji" cannot becolor-converted into green letters or only a red cloud portion cannot bepainted in blue, edit processing is considerably restricted.

In this embodiment, a memory for storing a non-rectangular area isarranged to overcome such high-grade edit processing.

FIG. 37A is a block diagram showing in detail a mask bit map memory 573Lfor restricting an area having an arbitrary shape, and its control. Thememory corresponds to the 100-dpi memory L in the entire circuit shownin FIG. 2, and is used as a means for generating switching signals fordetermining an ON (executing) or OFF (not executing) state of variousimage process and edit modes, such as the above-mentioned colorconversion, image trimming (non-rectangular trimming), image painting(non-rectangular painting), and the like for shapes illustrated in,e.g., FIG. 37E. More specifically, in FIG. 2, the switching signals aresupplied through signal lines BHi 123, DHi 122, FHi 121, GHi 119, PHi145, and AHi 148 as ON/OFF switching signals for the color conversioncircuit B, the color correction circuit D, the character synthesizingcircuit F, the image process and edit circuit G, the color balancecircuit P, and the external apparatus image synthesizing circuit 502.

Note that "non-rectangular area" described here does not exclude arectangular area, but includes it.

Since a mask is formed so that 4×4 pixels are used as one block and oneblock corresponds to one bit of a bit map memory. Therefore, in an imagehaving a pixel density of 16 pels/mm, for 297 mm×420 mm (A3 size),(297×420×16×16)÷16=2 Mbits, i.e., the mask can be formed by two 1-MbitDRAM chips.

In FIG. 37A, a signal 132 input to a FIFO memory 559L is anon-rectangular area data input line for generating a mask as describedabove. As the signal 132, an output signal 421 of the binarizationcircuit 532 shown in FIG. 2 is input through the switch circuit N.

The binarization circuit receives the signal from the reader A or theexternal apparatus interface M. When the signal 132 is input, it isinput to buffers 559L, 560L, 561L, and 562L corresponding to 1 bit×4lines in order to count the number of "1"s in the 4×4 block. FIFOmemories 559L to 562L are connected as follows. That is, as shown inFIG. 37A, the output of the FIFO memory 559L is connected to the inputof the memory 560L, and the output of the memory 560L is connected tothe input of the memory 561L. The outputs from the FIFO memories arelatched by latches 563L to 565L in response to a signal VCLK, so thatfour bits are in parallel with each other (see the timing chart of FIG.37D). An output 615L from the FIFO memory 559L, and outputs 616L, 617L,and 618L from the latches 563L, 564L, and 565L are added by adders 566L,567L, and 568L (signal 602L). The signal 602L is compared with a value(e.g., "12") set in a comparator 569L through an I/O port 25L by the CPU22. More specifically, it is checked if the number of "1"s in the 4×4block is larger than a predetermined value.

In FIG. 37D, the number of "1"s in a block N is "14", and the number of"1"s in a block (N+1) is "4". When the signal 602L represents "14", anoutput 603L of the comparator 569L in FIG. 37A goes to "1" level since"14">"12"; when the signal 602L represents "4", the output 603L goes to"0" level since "4"<"12". Therefore, the output from the comparator islatched once per 4×4 block by a latch 570L in response to a latch pulse605L (FIG. 37D), and the Q output of the latch 570L serves as a D_(IN)input of the memory 573L, i.e., mask generation data. An H addresscounter 580L generates a main scan address of the mask memory. Since oneaddress is assigned to a 4×4 block, the counter 580L counts up inresponse to a clock obtained by 1/4 frequency-dividing a pixel clockVCLK 608 by a frequency demultiplexer 577L. Similarly, a V addresscounter 575L generates a sub scan address of the mask memory. Thecounter 575L counts up in response to a clock obtained by 1/4frequency-dividing a sync signal HSYNC for each line for the same reasonas described above. The operations of the H and V address counters arecontrolled to be synchronized with a counting addition operation of "1"sin the 4×4 block.

Lower 2 bits 610L and 611L of the V address counter are logically NORedby a NOR gate 572L to generate a signal 606L for gating a 1/4frequency-divided clock 607L. Then, an AND gate 571L generates a latchsignal 605L for performing latching once per 4×4 block, as shown in thetiming chart of FIG. 37C. A data bus 616L is included in the CPU bus 22(FIG. 2), and can set non-rectangular area data in the bit map memory573L upon an instruction from the CPU 20. For example, as shown in FIG.37E, a circle or an ellipse is calculated by the CPU 20 (a sequencetherefor will be described later), and calculated data is written in thememory 573L, thereby generating a regular non-rectangular mask. In thiscase, for example, the radius or central position of the circle can beinput by numerical designation using a ten-key pad of the operation unit1000 (FIG. 2) or the digitizer 58. An address bus 613L is also includedin the CPU bus 22. A signal 615L corresponds to the write pulse WR fromthe CPU 20. In a WR mode of the memory 573L set by the CPU 20, the writepulse goes to "Lo" level, end gates 578L, 576L, and 581L are enabled.Thus, the address bus 613L and the data bus 616L from the CPU 20 areconnected to the memory 573L, and predetermined non-rectangular areadata is randomly written in the memory 573L. When WR (write) and RD(read) operations are sequentially performed by the H and V addresscounters, gates 576L' and 582L connected to the I/O port 25L are enabledby control lines of these gates, and sequential addresses are suppliedthe memory 573L.

For example, if a mask shown in FIG. 39 is formed by the output 421 fromthe binarization circuit 532 or by the CPU 20, trimming, synthesis, andthe like of an image can be performed on the basis of an area surroundedby a bold line.

Furthermore, the bitmap memory 573L shown in FIG. 37A can read outreduced or enlarged data by thinning or interpolation in both the H andV directions in the read mode. FIG. 40 shows in detail the H or Vaddress counter (580L, 575L) shown in FIG. 37A. As shown in FIG. 40, forexample, a signal MULSEL 636L is set to be "0" so that the B input of aselector 634L is to be selected. A thinning circuit (rate multiplier)635L for an input clock 614L thins data so that a clock CLK is generatedonce per three timing pulses, as shown in FIG. 41 (timing chart) (setupis made by an I/O port 641L) (637L). For example, "2" is set in a signal630L, and an output 638L from an address counter 632L and the value setin the signal 630L (e.g., "2") are added to each other only when athinned output 637L is output, and the sum is loaded in the counter.Therefore, as shown in FIG. 41, since the counter is incremented by "+2"every third clocks like 1→2→3→5→6→7→9, . . . , thus achieving 80%reduction. In an enlargement mode, since MULSEL="1" and an A input 614Lis selected, the address count is incremented like 1→2→3→3→4→5→6→6, . .. , as shown in the timing chart of FIG. 41.

FIG. 40 shows in detail the H and V address counters 580L and 575L shownin FIG. 37L. Since these circuits have the same hardware arrangement, adescription except for FIG. 37A will be omitted.

When the address counters are controlled in this manner, as shown inFIGS. 42A to 42C, an enlarged image 2 and a reduced image 1 aregenerated in response to an input non-rectangular area 1. Therefore,once a non-rectangular area is input, another input operation is notnecessary, and a zoom operation can be performed according to variousmagnifications using one mask plane.

The binarization circuit (532 in FIG. 2) and the high-density memory Kwill be described below. In FIG. 43A, the binarization circuit 532compares the video signal 113 output from the character/image correctioncircuit E with a threshold value 141k to obtain a binary signal. Thethreshold value is set by the CPU bus 22 in cooperation with theoperation unit. More specifically, if the level position of theoperation unit shown in FIG. 43C is set to be "M" (middle point), thethreshold value is "128" with respect to an amplitude value=256 of inputdata. As the level position is shifted toward a "+" direction, thethreshold value is changed by every "-30"; as it is shifted toward a "-"direction, the threshold value is changed by every "+30". Therefore, incorrespondence with "LOW→-2→-1→M→+1→+2→HIGH", the threshold value iscontrolled to change like "2˜→188→158→128→98→68→38".

As shown in FIG. 43A, two different threshold values are set by the CPUbus 22. These threshold values are switched by a selector 35k inaccordance with a switching signal 151, and the selected value is set ina comparator 32k as the threshold value. The switching signal 151 fromthe area signal generation circuit J can set another threshold valuewithin a specific area set by the digitizer 58. For example, asingle-color area of an original has a relatively low threshold value,and a multi-color area has a relatively high threshold value, so that auniform binary signal can always be obtained regardless of colors of anoriginal.

The memory K stores the binary signal 421 output as the signal 130 forone page. In this embodiment, since an image is processed at a densityof 400 dpi, the memory has a capacity of about 32 Mbits. FIG. 43D showsin detail the memory K. Input data D_(IN) 130 is gated by an enablesignal HE 528 from the area signal generation circuit J in a memorywrite mode, and is input to a memory 37k when a W/R 1 signal 549 fromthe CPU 20 is at "Hi" level in the write mode. At the same time, a Vaddress counter 35k for counting a main scan (horizontal) sync signalHSYNC 118 in response to a vertical sync signal ITOP 144 of an image togenerate a vertical address, and an H address counter 36k for countingan image transfer clock VCLK 117 in response to the signal HSYNC 118 togenerate a horizontal address corresponding to image data to be stored.In this case, as a memory WP input (write timing signal) 551k, a clockwhich is in-phase with the clock VCLK 117 is input as a strobe signal,and input data Di are sequentially stored in the memory 37k (timingchart of FIG. 44). When data is read out from the memory 37k, thecontrol signal W/R 1 is set at "Lo" level, thereby reading out outputdata D_(OUT) in the same sequence as described above. Both the datawrite and read access operations are performed in response to a signalHE 528. For example, when the signal HE 528 goes to "Hi" level at aninput timing of D₂ and goes to "Lo" level at an input timing of D_(m),as shown in FIG. 44, an image between D₂ and D_(m) is input to thememory 37k, no image is written in D₀, D₁, D_(m+1), and thereafter, anddata "0" is written instead. The same applies to the read mode. That is,during a period other than a "Hi" period of the signal HE, data "0" isread out. The signal HE is generated by the area signal generationcircuit J. More specifically, when a character original as shown in FIG.45 is placed on an original table, the signal HE in the write mode of abinary signal can be generated as shown in A of FIG. 45, so that abinary image of only a character portion can be fetched in the memory,as shown in FIG. 45A'.

Since the address counters 35k and 36k for reading out data from thememory 37k have the same arrangement as that shown in FIG. 40 and areoperated at the same timings shown in FIG. 41, when a binary characterimage shown in FIG. 46B, which is prestored in the memory, as shown inFIGS. 46A to 46D, is synthesized with an image shown in FIG. 46A, thetwo images can be synthesized after they are reduced, as shown in FIG.46C, or the two images can be synthesized after only a character portionto be synthesized is enlarged while the size of a background image (FIG.46A) is left unchanged, as shown in FIG. 46D.

FIG. 47 shows the switch circuit for performing distribution of datafrom the 100-dpi binary bit map memory L (FIG. 2) for a non-rectangularmask, and the 400-dpi binary memory K (FIG. 2) to the image processingblocks A, B, D, F, P, and G, switching distribution of binary videoimages to the memories L and K, and for selectably outputtingrectangular and non-rectangular area signals in real time. Real-timeswitching between the rectangular and non-rectangular area signals willbe described later. Mask data for restricting a non-rectangular areastored in the memory L is sent to, e.g., the color conversion circuit Bdescribed above (BHi 123), and color conversion is performed for aportion inside a shape shown in, e.g., FIG. 48B. The circuit in FIG. 47includes an I/O port 1n connected to the CPU bus 22, and 2 to 1selectors 8n to 13n, each of which selects the A input when a switchinginput S="9", and selects the B input when S="0". For example, in orderto supply the output from the 100-dpi mask memory L to the colorconversion circuit B, the selector 9n can select the A input, i.e.,28n="1", and an AND gate 3n can set a 21n input to be "1". Similarly,other signals can be arbitrarily controlled by inputs 16n to 31n.Outputs 30n and 31n from the I/O port in are control signals forselecting one of the binary memories L and K in which the output fromthe binarization circuit 532 (FIG. 2) is to be stored. When 30n="1", thebinary input 421 is input to the 100-dpi memory L; when 31n="1", it isinput to the 400-dpi memory K. When AHi 148="1", image data sent from anexternal apparatus is synthesized; when BHi 123="1", color conversion isperformed, as described above; and when DHi 122="1", monochromatic imagedata is calculated and output from the color correction circuit. SignalsFHi 121, PHi 145, GHi1 119, and GHi2 149 are respectively used forcharacter synthesis, color balance change, texture processing, andmosaic processing operations.

In this manner, the 100- and 400-dpi memories L and K are arranged, sothat character information is input to the high-density, i.e., 400-dpimemory K, and area information (including rectangular andnon-rectangular areas) is input to the 100-dpi memory L. Thus, charactersynthesis can be performed for a predetermined area, in particular, anon-rectangular area.

When a plurality of bit map memories are arranged, color windowprocessing shown in FIG. 62 can be achieved.

FIGS. 49A to 49F are views for explaining the area signal generationcircuit J. An area indicates, for example, a hatched portion of FIG.49E, and is distinguished from other areas by a signal AREA shown in thetiming chart of FIG. 49E during a sub scan period A→B. Each area isdesignated by the digitizer 58 shown in FIG. 2. FIGS. 49A to 49D show anarrangement wherein generation positions, durations of periods, and thenumbers of periods of a large number of area signals can be programmablyobtained by the CPU 20. In this arrangement, one area signal isgenerated by one bit of a RAM which can be accessed by the CPU. In orderto obtain, for example, n area signals AREA0 to AREAn, two n-bit RAMsare prepared (60j and 61j in FIG. 49D). Assuming that area signals AREA0and AREAn shown in FIG. 49B are to be obtained, "1" is set in bits "0"of addresses x₁ and x₃ of the RAM, and "0" is set in all bits of theremaining addresses. On the other hand, "1" is set at addresses 1, x₁,x₂, and x₄ of the RAM, and "0" is set in bits n of other addresses. Whendata in the RAM are sequentially read out in synchronism with apredetermined clock 117 with reference to the signal HSYNC 118, data "1"are read out at timings of the addresses x₁ and x₃, as shown in FIG.49C. Since the readout data are input to the J and K terminals of J-Kflip-flops 62j-0 to 62j-n, their outputs are subjected to a toggleoperation, i.e., when data "1" is read out from the RAM and the clockCLK is input, their outputs change like "0" to "1" or "1" to "0",thereby generating a period signal such as AREA0, i.e., an area signal.When data ="0"s over all the addresses, no area period is formed, and noarea is set. FIG. 49D shows the circuit arrangement of this circuit, and60j and 61j designate the above-mentioned RAMs. In order to switch areaperiods at high speed, for example, a memory write operation for settinga different area is performed by the CPU 20 for the RAM B 61j, whileread access of the RAM A 60j is performed in units of lines, so thatperiod generation and memory write access by the CPU are alternatelyswitched. Therefore, when a hatched area shown in FIG. 49F isdesignated, the RAMs A and B are switched like A→B→A→B→A. If (C₃, C₄,C₅)=(0, 1, 0) in FIG. 49D, a counter output counted in response to theclock VCLK 117 is supplied to the RAM A 60j (Aa) as an address through aselector 63j. In this case, a gate 66_(j) is enabled, and a gate 68j isdisabled, so that all the bit width, i.e., n bits are read out from theRAM A 60j and are input to the J-K flip-flops 62j-0 to 62j-n. Thus,period signals AREA0 to AREAn are generated in accordance with setvalues. Write access of the RAM B by the CPU is performed by an addressbus A-Bus, a data bus D-Bus, and an access signal R/W during thisperiod. In contrast to this, period signals can be generated on thebasis of data set in the RAM B 61j in the same manner as described aboveif (C₃, C₄, C₅)=(1, 0, 1) is set, and data write access of the RAM60_(j) by the CPU can also be executed.

The digitizer 58 performs area designation, and inputs coordinates of aposition designated by the CPU 20 through an I/O port. For example, inFIG. 50, if two points A and B are designated, coordinates A (X₁,Y₂) andB (X₂,Y₂) are input.

FIG. 37I is a view for explaining a method of executing process and editprocessing for rectangular and non-rectangular areas when an originalincludes both rectangular and non-rectangular images. In FIG. 37I, sgl1to sgln and ArCnt designate rectangular area signals, such as outputsAREA0 to AREAn of the rectangular area signal generation circuit shownin FIG. 49D.

On the other hand, Hi designates a non-rectangular area signal, such asan output 133 from the bit map memory L and its control circuit shown inFIG. 37A.

The signals sgl1 to sgln (h₂ 1 to h₂ n) are enable signals of processand edit processing. For a rectangular area, all the signalscorresponding to a portion to be subjected to the process and editprocessing are enabled. For a non-rectangular area, the signalscorresponding to only a rectangular area which inscribes thenon-rectangular area are enabled. More specifically, signalscorresponding to rectangular areas indicated by dotted lines are enabledfor non-rectangular areas indicated by solid lines A and B in FIG. 37N.

The signal ArCnt (h₃) is enabled in synchronism with the signals sgl1 tosgln for a rectangular area. For a non-rectangular area, the signalArCnt is disabled.

The signal Hi (h₂) is enabled within a non-rectangular area. For arectangular area, the signal Hi is disabled.

The Hi signal h₂ and the ArCnt signal h₃ are logically ORed by an ORgate h₁, and the logical sum is logically ANDed with the signals sgl1 tosgln (h₂ 1 to h₂ n) by AND gates h₃ 1 to h₃ n, respectively.

In this manner, outputs out1 to outn (h₄ 1 to h₄ n) allow a desiredcombination of rectangular and non-rectangular area signals.

FIGS. 37J to 37M are views for explaining changes in input signals whena rectangular area signal (B) and a non-rectangular area signal (A) arepresent at the same time.

The signals sgl1 to sgln (FIG. 37K) are enabled for the entirerectangular area, and for a rectangular area which inscribes anon-rectangular area, as described above.

The Hi signal (FIG. 37L) is disabled for a rectangular area, and isenabled for the entire non-rectangular area, as described above.

The signal ArCnt (FIG. 37M) is enabled for the entire rectangular area,and is disabled for the entire non-rectangular area, as described above.

Finally, a correspondence between FIGS. 37I and 47 will be describedbelow.

The OR gate h₁ shown in FIG. 37I corresponds to OR gates 38n and 39n inFIG. 47; the AND gates h₃ 1 to h₃ n in FIG. 37I, 4n to 7n, and 32n inFIG. 47; area signals sgl1 to sgln (h₂ 1 to h₂ n) in FIG. 37I, 33n to37n in FIG. 47; and the outputs out1 to outn (h₄ 1 to h₄ n) in FIG. 37I,DHi, FHi, PHi, GHi1, and GHi2 in FIG. 47.

In this manner, process and edit processing can be performed for aplurality areas including both rectangular and non-rectangular areas ofone original.

As described above, according to this embodiment, since a means fordesignating a rectangular area (area signals sgl1 to sgln), a means fordesignating a non-rectangular area (hit signals Hih₂), and anon-rectangular area real-time selection means (AND gates h₃ 1 to h₃ n)are arranged, edit processing can be performed for an original includingboth rectangular and non-rectangular area designation operations.

In particular, according to this embodiment, since signals sgl1 to sglndefine a rectangular area which inscribes a non-rectangular area, arectangular or non-rectangular area can be selected in accordance withthe non-rectangular area signal Hi and the rectangular area signalArCnt.

Area designation according to the nature of an area to be designated canbe performed. For example, when an area can be roughly designated, areadesignation can be performed using a rectangular area; when an area mustbe exactly designated, area designation can be performed using anon-rectangular area. Thus, edit processing with a high degree offreedom can be efficiently performed.

The number of areas and the number of AND gates can be desirably set.The kinds of processing performed for each area can be desirablydetermined by setting the I/O port 1n based on inputs from the operationunit 1000.

FIG. 51 shows the interface M for performing bidirectional communicationof image data with an external apparatus connected to the imageprocessing system of this embodiment. An I/O port 1m is connected to theCPU bus 22, and outputs signals 5m to 9m for controlling directions ofdata buses A0 to C0, A1 to C1, and D. Bus buffers 2m and 3m haveterminals for an output tristate control signal E. The buffer 3m canchange its direction in accordance with the D input. When E input="1",the buffers 2m and 3m output signals; when E="0", they are set in anoutput high-impedance state. A 3 to 1 selector 10m selects one of threeparallel inputs A, B, and C in accordance with select signals 6m and 7m.In this circuit, basically, there are bus flows of 1. (A0, B0, C0)→(A1,B1, C1) and 2. (A1, B1, C1)→D. These bus flows are controlled by the CPU20 as shown in the truth table of FIG. 52. This system can receive botha rectangular image (FIG. 53A) and a non-rectangular image (FIG. 53B),which are input from an external apparatus through the buses A1, A2, andA3. When a rectangular image shown in FIG. 53A is input, the I/O port501 outputs a control signal 147 so that the switching input of theselector 503 shown in FIG. 2 is set to be "1" to select the A input. Atthe same time, predetermined data are written by the CPU atpredetermined addresses of the RAMs 60j and 61j (FIG. 51) in the areasignal generation circuit J, which correspond to areas to besynthesized, thereby generating a rectangular area signal 129. In anarea where an image input 128 from the external apparatus is selected bythe selector 507, not only the image data 128 but also thegradation/resolution switching signal 140 are simultaneously switched.More specifically, in an area where an image from the external apparatusis input, the gradation/resolution switching signal which is generatedbased on a character area signal MjAr 124 (FIG. 2) detected from colorseparation signals of an image read from an original table, is stopped,and is forcibly set at "Hi" level, thereby smoothly outputting an imagearea to be synthesized from the external apparatus with multigradation.As has been described above with reference to FIG. 51, when the bit mapmask signal Ahi 148 from the binary memory L is selected by the selector503 in response to the signal 147, synthesis of an image from theexternal apparatus can be realized, as shown in FIG. 53B.

<Summary of Operation Unit>

FIG. 54 schematically shows an outer appearance of the operation unit1000 according to this embodiment. A key 1100 serves as a copy startkey. A key 1101 serves as a reset key, and is used to reset all setvalues on the operation unit to power-on values. A key 1102 is aclear/stop key, and is used to reset an input count value upondesignation of a copy count or to interrupt a copying operation. A keygroup 1103 is a ten-key pad, and is used to input numerical values, suchas a copy count, a magnification, and the like. A key 1104 is anoriginal size detection key. A key 1105 is a center shift designationkey. A key 1106 is an ACS function (black original recognition) key.When an ACS mode is ON, an original in signal black color is copied inblack. A key 1107 is a remote key which is used to transfer the right ofcontrol to a connected apparatus. A key 1108 is a preheat key.

A liquid crystal display 1109 displays various kinds of information. Thesurface of the display 1109 serves as a touch panel. When the surface ofthe display 1109 is pressed by, e.g., a finger, a coordinate value ofthe pressed position is fetched.

In a normal or ordinary state, the display 1109 displays amagnification, a selected sheet size, a copy count, and a copy density.During setting of various copy modes, guide screens necessary forsetting the corresponding modes are sequentially displayed. (The copymode is set by soft keys displayed on the screen.) In addition, thedisplay 1109 displays a self-diagnosis screen of a guide screen.

A key 1110 is a zoom key which serves as an enter key of a mode ofdesignating a zoom magnification. A key 1111 is a zoom program key,which serves as an enter key of a mode of calculating a magnificationbased on an original size and a copy size. A key 1112 is an enlargementserial copy key, which serves as an enter key of an enlargement serialcopy mode. A key 1113 is a key for setting a fitting synthesizing mode.A key 1114 is a key for setting a character synthesizing mode. A key1115 is a key for setting a color balance. A key 1116 is a key forsetting color modes, e.g., a monochrome mode, a negative/positivereversal mode, and the like. A key 1117 is a user's color key, which canset an arbitrary color mode. A key 1118 is a paint key, which can set apaint mode. A key 1119 is a key for setting a color conversion mode. Akey 1120 is a key for setting an outline mode. A key 1121 is a key forsetting a mirror image mode. Keys 1124 and 1123 are keys forrespectively designating trimming and masking modes. A key 1122 can beused to designate an area, and processing of a portion inside the areacan be set independently of other portions. A key 1129 serves as anenter key of a mode for performing an operation for reading a textureimage, and the like. A key 1128 serves as an enter key of a mosaic mode,and is used to change, e.g., a mosaic size.

A key 1127 serves as an enter key of a mode for adjusting sharpness ofan edge of an output image. A key 1126 is a key for setting an imagerepeat mode for repetitively outputting a designated image.

A key 1125 is a key for enabling inclination/taper processing of animage. A key 1135 is a key for changing a shift mode. A key 1134 is akey for setting a page serial copy mode, an arbitrary division mode, andthe like. A key 1133 is used to set data associated with a projector. Akey 1132 serves as an enter key of a mode of controlling an optionalapparatus connected. A key 1131 is a recall key, which can recall up toprevious three set contents. A key 1130 is an asterisk key. Keys 1136 to1139 are mode memory call keys, which are used to call a mode memory tobe registered. Keys 1140 to 1143 are program memory call keys, which areused to call an operation program to be registered.

<Color Conversion Operation Sequence>

A sequence of the color conversion operation will be described belowwith reference to FIG. 55.

When the color conversion key 1119 on the operation unit is depressed,the display 1109 displays a page or image plane P050. An original isplaced on the digitizer, and a color before conversion is designatedwith a pen. When an input is completed, the screen display is switchedto a page P051. On this page, a width of the color before conversion isadjusted using touch keys 1050 and 1051. After the width is set, a touchkey 1052 is depressed. The screen display is switched to a page P052,and whether or not a color density is changed after color conversion isselected using touch keys 1053 and 1054. When "density change" isselected, the converted color has gradation in correspondence with acolor density before conversion. That is, the above-mentioned gradationcolor conversion is executed. On the other hand, when "density unchange"is selected, the color is converted to a designated color at an equaldensity. When "density change/unchange" is selected, the screen displayis switched to a page P053, a kind of color after conversion isselected. When a key 1055 is depressed on the page P053, an operator candesignate an arbitrary color on the next page P054. When a coloradjustment key is depressed, the screen display advances to a page P055,and color adjustment can be performed for each of Y, M, C, and Bk inunits of 1%.

When a key 1056 is depressed on the page P053, the screen displayadvances to a page P056, and a desired color of an original on thedigitizer is designated with a pointing pen. On the next page P057, acolor density can be adjusted.

When a key 1057 is depressed on the page P053, the screen displayadvances to a page P058, and a predetermined registration color can beselected by a number.

<Trimming Area Designation Sequence>

A trimming area designation sequence (the same applies to masking, andalso applies to partial processing and the like in terms of a method ofdesignating an area) will be described below with reference to FIGS. 56and 57.

The trimming key 1124 on the operation unit 1000 is depressed. When thedisplay 1109 displays a page P001, two diagonal points of a rectangleare input using the digitizer, and a page P002 is then displayed, sothat a rectangular area can be successively input. When a plurality ofareas are designated, a previous area key 1001 on the page P001 and asucceeding area key 1002 are depressed in turn, so that designated areason an X-Y coordinate system can be recognized like in the page P002.

In this embodiment, a non-rectangular area can be designated using thebit map memory. During display of the page P001, a touch key 1003 isdepressed to display a page P003. On the page P003, a desired pattern isselected. When necessary coordinates of a circle, an oval, an Rrectangle, or the like are input, the CPU 20 develops it into the bitmapmemory by calculations. When a free pattern is selected, a desiredpattern is traced using a pointing pen of the digitizer 58, therebycontinuously inputting coordinates. The input values are processed andare recorded on a bit map.

Non-rectangular area designation will be described in detail below.

(Circular Area Designation)

When a key 1004 is depressed on the page P003, the display 1009 thendisplays a page P004, and a circular area can be designated.

Circular area designation will be described below with reference to theflow chart of FIG. 58. In step S101, a central point is input using thedigitizer 58 shown in FIG. 2 (P004). The display 1009 then displays apage P005, and in step S103, one point on a circumference of a circlehaving a radius to be designated is input by the digitizer 58. In stepS105, the input coordinate value is converted to a coordinate value inthe bit map memory L (100-dpi binary memory) in FIG. 2 by the CPU 20.

In step S107, a coordinate value of another point on the circumferenceis calculated. In step S109, a bank of the bit map memory L is selected,and in step S111, the calculation results are input to the bit mapmemory L via the CPU bus 22. In FIG. 37A, the data is input to thedriver 578L through the CPU DATA bus 616L, and is then written in thebitmap memory through a signal line 604L. Since address control hasalready been described, a description thereof will be omitted. Thisoperation is repeated for all the points on the circumference (S113),thus completing circular area designation.

Note that in place of inputting data calculated by the CPU 20, templateinformation corresponding to information of two points input in advanceis stored in the ROM 11, and the two points are designated by thedigitizer to directly write data in the bit map memory L withoutcalculations.

(Oval Area Designation)

When a key 1005 is depressed on the page P003, the display advances to apage 007. The oval area designation will be described below withreference to the flow chart of FIG. 59.

In step S202, two diagonal points of a maximum rectangular area whichinscribes an oval are designated by the digitizer 58. Coordinate valuesof the circumferential portion are written in the bit map memory L insteps 8206 to 8212 in the same manner as in the circular areadesignation.

Coordinate values of straight line portions are written in the memory Lin steps S214 to S220, thus completing area designation. Note thattemplate information may be prestored in the ROM 11 as in the circulararea designation.

(R Rectangular Area Designation)

A designation method of an R rectangle is the same as that of an oval aswell as a memory write access method, and a detailed description thereofwill be omitted.

The circle, the oval, and the R rectangle have been exemplified. Othernon-rectangular areas can be designated on the basis of templateinformation, as a matter of course.

On pages P006, P008, P010, and P102, a clear key (1009 to 1012) isdepressed after each pattern is input, so that a content in the bit mapmemory can be partially deleted.

Therefore, when a pattern is erroneously designated, only two-pointdesignation can be immediately cleared, and can be performed again.

A plurality of areas can be successively designated. When a plurality ofareas are designated, upon execution of processing of overlapping areas,an area designated later is preferentially processed. Alternatively,areas designated earlier may have priority over others.

FIG. 57 shows an output example of oval trimming by the above-mentionedsetting method.

<Operation Sequence Associated With Character Synthesis>

An operation sequence associated with character synthesis will bedescribed below with reference to FIGS. 60, 61, and 62. When thecharacter synthesizing key 1114 on the operation unit is depressed, theliquid crystal display 1109 displays a page P020. When a characteroriginal 1201 to be synthesized is placed on the original table, and atouch key 1020 is depressed, the character original is read, the readimage information is subjected to binarization processing, and theprocessed image information is stored in the bit map memory (FIG. 2).Since the detailed processing means have already been described, arepetitive description thereof will be avoided. In this case, in orderto designate a range of an image to be stored, a touch key 1021 on thepage P020 is depressed to display a page P021. The character original1201 is placed on the digitizer 58, and a range is designated bypointing two points using the pointing pen of the digitizer. Uponcompletion of the designation, the screen display advances to a pageP022, and whether a portion inside the designated range is read(trimming) or a portion outside the designated range is read (masking)is selected using touch keys 1023 and 1024. In some character originals,it is difficult to extract a character portion from them duringbinarization processing. In this case, a touch key 1022 on the page P020is depressed to display a page P023, so that the slice level of thebinarization processing can be adjusted using touch keys 1025 and 1026.

In this manner, since the slice level can be manually adjusted,appropriate binarization processing can be performed according to acharacter color or width of an original.

Furthermore, a touch key 1027 is depressed, and an area is designated onpages P024' and P025', so that a slice level can be partially modifiedon a page P026'.

In this manner, an area is designated, and the slice level of only thedesignated area can be changed. Thus, even when a black characteroriginal partially includes, e.g., yellow characters, the slice levelsof black and yellow characters are separately and appropriately set, sothat satisfactory binarization processing can be performed for theentire characters.

In this case, the above-mentioned processing can be executed accordingto non-rectangular area information stored in the binary memory L shownin FIG. 2, as a matter of course.

Upon completion of reading of the character original, the display 1109displays a page P024 shown in FIG. 61.

In order to select color background processing, a touch key 1027 on thepage P024 is depressed to display a page P025. A color of a character tobe synthesized is selected from displayed colors. A character color canbe partially changed. In this case, a touch key 1029 is depressed todisplay a page P027, and an area is designated. Thereafter, a charactercolor is selected on a page P030. Furthermore, color frame makingprocessing can be added to a frame of a character to be synthesized. Inthis case, a touch key 1031 on the page P030 is depressed to display apage P032, and a color of a frame is selected. In this case, coloradjustment can be performed as in the color conversion described above.Furthermore, a touch key 1033 is depressed, and a frame width isadjusted on a page P041.

A case will be described below wherein tiling processing (to be referredto as window processing hereinafter) is added to a rectangular areaincluding characters to be synthesized. A touch key 1028 on the pageP024 is depressed to display a page P034, and an area is designated.Window processing is executed within a range of the designated area.Upon completion of the area designation, a character color is selectedon a page P037. A touch key 1032 is then depressed to display a pageP039, and a window color is selected.

In the color selection, a touch key 1030 as a color adjustment key isdepressed on the page P025 to display a page P026, and a density of aselected color can be changed.

Character synthesis is performed in the above-mentioned sequence. FIG.62 shows an output example obtained when the above-mentioned settingmethod is actually executed.

Note that not only a rectangular area but also a non-rectangular areacan be designated.

<Texture Processing Setting Sequence>

The texture processing will be described below with reference to FIG.63A.

When the texture key 1129 on the operation unit 1000 is depressed, thedisplay 1109 displays a page P060. When the texture processing is to beexecuted, a touch key 1060 is depressed to be reverse-displayed. When animage pattern for the texture processing is loaded in the texture imagememory (113g in FIG. 32), a touch key 1061 is depressed. In this case,if the pattern has already been stored in the image memory, a page P062is displayed, and when no image can be displayed, a page P061 isdisplayed. An original of an image to be read is placed on the originaltable, and a touch key 1062 is depressed, so that image data can bestored in the texture image memory. In order to read an arbitraryportion of the original, a touch key 1063 is depressed, and designationis made on a page P063 using the digitizer 58. Designation can be madeby pointing one central point of a 16 mm×16 mm reading range by apointing pen.

Reading of a texture pattern by designating one point can be performedas follows.

When the touch key 1060 is depressed to set texture processing withoutreading a pattern, and the copy start key 1100, or other mode keys (1110to 1143), or a touch key 1064 is depressed to leave the page P064, thedisplay 1109 generates warning as shown in a page P065.

The size of the reading range may be designated by an operator using theten-key pad.

FIG. 63B-2 shows the flow chart of the CPU 20 when a texture pattern isread as shown in FIG. 63B-1.

In the texture mode, it is checked if coordinates of a central point ofa portion (in this embodiment, a square is exemplified but otherfigures, e.g., a rectangle may be available) used as a texture patternon an original is input from the digitizer 58 (S631). In this case, thecoordinate input is recognized by (x,y) coordinates of an input point,as shown in a block S631'. If NO in step S631, an input is waited;otherwise, write star, and end addresses in the horizontal and verticaldirections are calculated (S632') and are set in the counters (S632). Inthis case, if lengths a of vertical and horizontal sides are set to bedifferent from each other, a rectangular pattern can be formed. Imagedata is then read by scanning the reader A, and the image data at apredetermined position is written in the texture memory 113g (FIG. 32)(S633). Thus, the storage operation of the texture pattern is completed,and a normal copying operation is performed in the above-mentionedmethod (step S634) to synthesize the texture pattern.

According to this embodiment, when one point is designated on thedigitizer, the texture pattern can be read, and operability can beremarkably improved.

<Mosaic Processing Setting Sequence>

FIG. 64A is a view for explaining a sequence for setting mosaicprocessing.

When the mosaic key 1128 on the operation unit is depressed, the display1109 displays a page P100. In order to perform mosaic processing of anoriginal image, a touch key 1400 is depressed and reverse-displayed.

A mosaic size upon execution of mosaic processing is changed on a pageP101 displayed by depressing a touch key 1401. The mosaic size can bechanged independently in both the vertical (Y) and horizontal (X)directions.

FIG. 64B is a flow chart showing a setting operation of the mosaic size.When the mosaic mode is set, the CPU 20 checks if a mosaic size (X, Y)is input from the liquid crystal touch panel 1109 (S641). If NO in stepS641, an input is waited; otherwise, parameters (X, Y) are set in mosaicprocessing registers (in 402g in FIG. 34) in the digital processor(S642). Based on these parameters, mosaic processing is executed by theabove-mentioned method in a size of X mm (horizontal direction)×Y mm(vertical direction).

In this embodiment, since the mosaic size can be set independently inthe vertical and horizontal directions, various needs on image editprocessing can be met. In particular, this mode can be widely utilizedin the field of design.

<* Mode Operation Sequence>

FIG. 65 is a view for explaining an * mode operation sequence.

When the * key 1130 on the operation unit 1000 is depressed, the controlenters the * mode, and the display 1109 displays a page P110. Upondepression of a touch key 1500, a color registration mode forregistering a paint user's color and color information used in colorconversion or color character is set. Upon depression of a touch key1501, a function of correcting an image omission caused by a printer isturned on/off. A touch key 1502 is used to start a mode memoryregistration mode. A touch key 1503 is used to start a mode ofdesignating a manual feed size. A touch key 1504 is used to start aprogram memory registration mode. A touch key 1505 is used to start amode of setting a default value of color balance.

(Color Registration Mode)

When the touch key 1500 is depressed during display of the page P110,the color registration mode is started. The display 1109 displays a pageP111, and a kind of color to be registered is selected. When palletcolors are to be changed, a touch key 1506 is depressed, and a color tobe changed is selected on a page P116. On a page P117, values of yellow,magenta, cyan, and black components can be adjusted in units of 1%.

When an arbitrary color on an original is to be registered, a touch key1507 is depressed, and a registration number is selected on a page P118.A color to be registered is then designated using the digitizer 58. On apage P120, an original is set on the original table, and a touch key1510 is depressed to register a desired color.

(Manual Feed Size Designation)

As shown in a page P112, a manual feed size can be selected from bethstandard and specific sizes.

A specific size can be designated in units of 1 mm in both thehorizontal (X) and vertical (Y) directions.

(Mode Memory Registration)

As shown in a page P113, a set mode can be registered in the modememory.

(Program Memory Registration)

As shown in a page P114, a series of programs for performing areadesignation and predetermined processing operations can be registered.

(Color Balance Registration)

As shown in a page P115, color balance of each of Y, M, C, and Bk can beregistered.

<Program Memory Operation Sequence>

A registration operation of the program memory and its use sequence willbe explained below with reference to FIGS. 66 and 67.

The program memory has a memory function of storing operation sequencesassociated with setting operations, and reproducing the storedsequences. In this function, necessary modes can be combined, or settingoperations can be made while skipping unnecessary pages. For example, asequence for executing zoom processing of a certain area and setting animage repeat mode will be programmed below.

The * key 1130 on the operation unit is depressed to display a page P080on the display, and a touch key 1200 as a program memory key is thendepressed. In this embodiment, a maximum of four programs can beregistered. On the page P081, a number to be registered is selected.Thereafter, a program registration mode is started. In the programregistration mode, a page 1300 in FIG. 68A in a normal mode is displayedlike a page 1301 as shown in FIG. 68B. A touch key 1302 as a skip key isdepressed when a present page is to be skipped. A touch key 1303 as aclear key is used to interrupt registration during the program memoryregistration mode, and to restart registration. A touch key 1304 as anend key is used to leave the program memory registration mode and toregister a program in a memory having a number determined first.

The trimming key 1124 on the operation unit is depressed, and an area isdesignated by the digitizer. In this case, the display 1109 displays apage P084. However, if no more area designation is required, a touch key1202 is depressed to skip this page (a page P085 is displayed in turn).

When the zoom key 1110 on the operation unit is depressed, the display1109 displays a page P086. A magnification is set on this page, and atouch key 1203 is then depressed to turn a display to a page P087.Finally, the image repeat key 1126 on the operation unit is depressed,and a setting operation associated with the image repeat mode isperformed on the page P088. Thereafter, a touch key 1204 is depressed toregister the above program in the program memory No. 1.

In order to call the program registered in the above-mentioned sequence,the key 1140 for calling the program memory "1" on the operation unit isdepressed. The display 1109 displays a page P091 to wait for an areainput. When an area is input using the digitizer, the display 1109displays a page P092, and then turns it to the next page P093. When amagnification is set on this page and a touch key 1210 is depressed, thedisplay 1109 displays a page P094, and the image repeat mode can be set.When a touch key 1211 is depressed, the control leaves a mode utilizingthe program memory (to be referred to as a trace mode hereinafter).While the program memory is called and a programmed operation isexecuted, the edit mode keys (1110 to 1143) are invalidated, and anoperation can be executed according to a registered program.

FIG. 69 shows a registration algorithm of the program memory. Turning ofa page or image plane in step S301 is to rewrite a display of the liquidcrystal display using keys or touch keys. When the touch key 1302 isdepressed to skip the presently displayed image plane (S303), skipinformation is set in a record table when the next image plane is turned(S305). In step S307, the number of a new image plane or a new imageplane number is set on the record table. When a clear key is depressed,the record table is entirely cleared (S309, S311); otherwise, the flowreturns to step S301 to display the next image plane. FIG. 71 shows aformat of a record table. FIG. 70 shows an algorithm of an operationafter the program memory is called.

If it is determined in step S401 that an image plane is to be turned, itis checked if a new image plane is a standard image plane (S403). If YESin step S403, the flow advances to step S411, and the next image planenumber is set from the record table; otherwise, the new image planenumber is compared with an image plane number predetermined in therecord table (S405). If a coincidence between the two numbers isdetected, the flow advances to step S409. If a skip flag is detected,the flow returns to step S401 while skipping step S411. If anoncoincidence is detected in step S405, recovery processing is executed(S407), and an image plane is then turned.

A means for switching a printing resolution and outputting an imageaccording to the present invention will be described below. This meansswitches a printing resolution on the basis of the resolution switchingsignal 140 generated according to character and halftone portionsseparated by the above-mentioned character/image area separation circuitI, and corresponds to the driver shown in FIG. 2. In this embodiment, acharacter portion is printed at a high resolution of 400 dpi, and ahalftone portion is printed at 200 dpi. This means will be described indetail below. A PWM circuit 778 as a portion of the driver shown in FIG.2 is included in a printer controller 700 of the printer 2 shown inFIG. 1. The PWM circuit 778 receives the video data 138 as a finaloutput of the overall circuit shown in FIG. 2, and the resolutionswitching signal 143 to perform ON/OFF control of a semiconductor laser711L shown in FIG. 76.

The PWM circuit 778, as a portion of the driver shown in FIG. 2, forsupplying a signal for outputting a laser beam will be described indetail below.

FIG. 73A is a block diagram of the PWM circuit, and FIG. 73B is a timingchart thereof.

The input video data 138 is latched by a latch 900 in response to aleading edge of a clock VCLK 117 to be synchronized with clocks (800,801 in FIG. 73B). The video data 138 output from the latch is subjectedto gradation-correction by an LUT (look-up table) 901 comprising a ROMor RAM. The corrected image data is D/A-converted into one analog videosignal by a D/A (digital-to-analog) converter 902. The generated analogsignal is input to the next comparators 910 and 911, and is comparedwith triangle waves (to be described later). Signals 808 and 809 inputto the other input terminal of each comparator are triangle waves (808and 809 in FIG. 73B) which are synchronized with the clock VCLK and areseparately generated. More specifically, one wave is a triangle wave WV1which is generated by a triangle wave generation circuit 908 inaccordance with a triangle wave generation reference signal 806 obtainedby 1/2 frequency-dividing a sync clock 2VCLK 117' having a frequencytwice that of the clock VCLK 801 by a J-K flip-flop 906, and the otherwave is a triangle wave WV2 generated by a triangle wave generationcircuit 909 in accordance with the clock 2VCLK. Note that the clock2VCLK 117' is generated by a multiplier (not shown) based on the clockVCLK 117. The triangle waves 808 and 809 and the video data 138 aregenerated in synchronism with the clock VCLK, as shown in FIG. 78B. Aninverted HSYNC signal initializes the flip-flop 906 to be synchronouswith an HSYNC signal 118 generated synchronous with the clock VCLK. Withthe above operation, signals having pulse widths shown in FIG. 73Caccording to the value of the input video data 138 can be obtained asoutputs 810 and 811 of the comparators CMP1 910 and CMP2 911. Morespecifically, in this system, when an output from an AND gate 913 shownIn FIG. 73A is "1", a laser is turned on, and prints dots on a printsheet; when the output is "0", the laser is turned off, and printsnothing on the print sheet. Therefore, an OFF state of the laser can becontrolled by a control signal LON (805) from the CPU 20. FIG. 73C showsa state wherein the level of an image signal Di changes from "black" to"white" from the left to the right. Since "white" data is input as "FF"and "black" data is input as "00" to the PWM circuit, the output fromthe D/A converter 902 changes like Di shown in FIG. 73C. In contrast tothis, since the triangle waves change, as indicated by WV1 (A) and WV2(ii), the pulse widths of the outputs of the comparators CMP1 and CMP2are decreased as the level shifts from "black" to "white"0, as indicatedby PW1 and PW2. As can be seen from FIG. 73C, when PW1 is selected, dotsare formed on a print sheet to have intervals of P₁ →P₂, and a change inpulse width has a dynamic range of W1. On the other hand, when PW2 isselected, dots are formed to have intervals of P₃ →P₄ →P₅ →P₆, and adynamic range of a change in pulse width is W2. Thus, the dynamic rangeof PW2 is 1/2 that of PW1. For example, a printing density (resolution)is set to be about 200 lines/inch for PW1, and is set to be about 400lines/inch for PW2. As can be understood from this, when PW1 isselected, gradation can be improved about twice that of PW2, while whenPW2 is selected, a resolution can be remarkably improved. Thus, thereader (FIG. 1) supplies the signal LCHG 143 So that when a highresolution is required, PW2 is selected, and when multigradation isrequired, PW1 is selected. More specifically, a selector 912 shown inFIG. 73A selects the A input, i.e., PW1 when LCHG 143="0". WhenLCHG="1", PW2 is output from an output terminal O of the selector 912.The laser is turned on by a finally obtained pulse width, therebyprinting dots.

The LUT 901 is a table conversion ROM for gradation correction. The LUT901 receives address signals C₂ 812', C₁ 812, and C₀ 813, a tableswitching signal 814, and a video signal 815, and outputs correctedvideo data. When the signal LCHG 143 is set to be "0" to select PW1, abinary counter 903 outputs all "0"s, and a PW1 correction table in theLUT 901 can be selected. The signals C₀, C₁, and C₂ are switchedaccording to a color signal to be output. For example, when C₀, C₁, C₂="0, 0, 0", a yellow signal is output; when "0, 1, 0", magenta; when "1,0, 0", cyan; and when "1, 1, 0", black as in the masking processing.That is, gradation correction characteristics are switched in units ofcolor images to be printed. In this manner, differences in gradationcharacteristics caused by differences in image reproductioncharacteristics of the laser beam printer depending on colors can becompensated for. Upon combination of C₂, C₀, and C₁, gradationcorrection over a wide range can be performed. For example, gradationswitching characteristics of each color can be switched according to akind of input image. When the signal LCHG is set to be "1" to selectPW1, the binary counter counts sync signals of a line, and outputs"1"→"2"→"1"→"2"→, . . . to the address input 814 of the LUT. Thus, agradation correction table is switched in units of lines, thus furtherimproving gradation.

This will be described in more detail with reference to FIGS. 74A and74B. A curve A shown in FIG. 74A is an input data vs. printing densitycharacteristic curve when input data is changed from "FF", i.e., "white"to "0", i.e., "black". A standard characteristic curve K is preferable,and hence, a gradation correction table is set up with a characteristiccurve B as characteristics opposite to the curve A. FIG. 74A showsgradation correction characteristics A and B in units of lines when PW1is selected. When a pulse width in the main scan direction (laser scandirection) is varied by the above-mentioned triangle wave, two stages ofgradation are provided in the sub scan direction (image feed direction),thus further improving gradation characteristics. More specifically, aportion suffering from an abrupt change in density is reproduced basedmainly on the characteristic curve A, and flat gradation is reproducedby the characteristic curve B. Therefore, even when PW2 is selected, asdescribed above, a certain gradation level can be assured at a highresolution. When PW1 is selected, very good gradation characteristicscan be guaranteed.

The pulse-width modulated video signal is applied to a laser driver 711Lthrough a line 224, thereby modulating a laser beam LB.

Note that the signals C₀, C₁, C₂, and LON in FIG. 74A are output from acontrol circuit (not shown) in the printer controller 700 shown in FIG.2.

A case will be examined below wherein a color original including acharacter area is to be processed. Referring back to the overall circuitdiagram of FIG. 2, a processing sequence will be described below. Morespecifically, after input image data including both character andhalftone images passes through an input circuit (A block), one is inputto the LOG conversion circuit (C) and the color correction circuit (D)to obtain an appropriate image, and the other is input to a detectioncircuit (I) for separating a halftone area. Thus, detection signals MjAr(124) to SCRN (127) according to character and halftone areas areoutput. Of these detection signals, the signal MjAr (124) is a signalrepresenting a character portion. The character/image correction circuitE generates the resolution switching signal LCHG (140 in FIG. 2, 140 inFIG. 21) based on the signal MjAr, as has been described above. As shownin FIG. 2, the signal LCHG 140 is separately sent to the printer to beparallel to multi-value video signals 113, 114, 115, 116, and 138, andserves as a switching signal for outputting a character portion at ahigh resolution (400 dpi) and outputting a halftone portion withmultigradation (200 dpi).

The following processing is performed, as described above.

Image Forming Operation!

The laser beam LB modulated in correspondence with image output data 816is horizontally scanned at high speed in an angular interval of arrowsA-B by a polygonal mirror 712 which is rotated at high speed, and formsan image on the surface of a photosensitive drum 715 via an f/θ lens 713and a mirror 714, thus performing dot-exposure corresponding to imagedata. One horizontal scan period of the laser beam corresponds to thatof an original image, and corresponds to a width of 1/16 mm in a feeddirection (sub scan direction) in this embodiment.

On the other hand, the photosensitive drum 715 is rotated at a constantspeed in a direction of an arrow L shown in FIG. 75. Since scanning ofthe laser beam is performed in the main scan direction of the drum andthe photosensitive drum 715 is rotated at a constant speed in the subscan direction, an image is sequentially exposed, thus forming a latentimage. A toner image is formed by uniform charging by a charger 717prior to exposure→the above-mentioned exposure→toner developing by adeveloping sleeve 731. For example, when a latent image is developed bya yellow toner of a developing sleeve 713Y in correspondence with thefirst original exposure-scanning in the color reader, a toner imagecorresponding to a yellow component of an original 3 is formed on thephotosensitive drum 715.

The yellow toner image is transferred to and formed on a sheet 791 whoseleading end is carried by grippers 751 and which is wound around atransfer drum 716 by a transfer charger 729 arranged at a contact pointbetween the photosensitive drum 715 and the transfer drum 716. The sameprocessing is repeated for M (magenta), C (cyan), and Bk (black) imagesto overlap the corresponding toner images on the sheet 791, thus forminga full-color image using four colors of toners.

Thereafter, the sheet 791 is peeled from the transfer drum 716 by amovable peeling pawl 750 shown in FIG. 1, and is then guided to an imagefixing unit 743 by a conveyor belt 742. Thus, the toner images on thesheet 791 are welded and fixed by heat and press rollers 744 and 745 ofthe fixing unit 743.

In this embodiment, the printing driver drives the color laser beamprinter. The present invention can also be applied to color imagecopying machines such as a thermal transfer color printer, an ink-jetcolor printer, and the like for obtaining a color image as long as theyhave a function of switching a resolution according to images.

As described above, according to the present invention, there can beprovided an image processing apparatus which can discriminate an imageor character portion of input image data by a simple circuitarrangement, and can simultaneously reproduce a smooth image and a sharpcharacter in real time.

What is claimed is:
 1. An image processing method comprising:an inputstep of inputting image data; a discriminating step of discriminating atype of an image represented by the image data; a setting step ofsetting a discrimination standard of said discriminating step; and adisplay step of displaying a condition in said setting step.
 2. A methodaccording to claim 1, wherein said discriminating step discriminates aline image portion of the image based on the image data.
 3. A methodaccording to claim 2, wherein said setting step sets a parameter fordiscriminating, in said discriminating step, the line image portion ofthe image.
 4. A method according to claim 1, wherein the image datainput in said input step includes a plurality of color components.
 5. Amethod according to claim 4, further comprising a step of detecting ablack portion of the image based on the image data input in said inputstep.
 6. A method according to claim 5, further comprising a step ofjudging a black character portion of the image data input in said inputstep when the black portion of the image is detected in said detectingstep.
 7. A method according to claim 6, further comprising a step ofprocessing the image data input in said input step in accordance with ajudging result of said judging step.
 8. A method according to claim 7,wherein said setting step controls an intensity of the process which isperformed for the black character portion in said processing step.
 9. Amethod according to claim 1, wherein said setting step and said displaystep utilize a touch panel display.
 10. An image processing apparatuscomprising:input means for inputting image data; discriminating meansfor discriminating a type of an image represented by the image data;setting means for setting a discrimination standard of saiddiscriminating means; and display means for displaying a condition ofsaid setting means.
 11. An apparatus according to claim 10, wherein saiddiscriminating means discriminates a line image portion of the imagebased on the image data.
 12. An apparatus according to claim 11, whereinsaid setting means sets a parameter for discriminating the line imageportion of the image by said discriminating means.
 13. An apparatusaccording to claim 10, wherein the image data input by said input meansincludes a plurality of color components.
 14. An apparatus according toclaim 13, further comprising detecting means for detecting a blackportion of the image data input by said input means.
 15. An apparatusaccording to claim 14, further comprising judging means for judging ablack character portion of the image data input by said input means whensaid detecting means detects the black portion of the image.
 16. Anapparatus according to claim 15, further comprising processing means forprocessing the image data input by said input means in accordance with ajudging result of said judging means.
 17. An apparatus according toclaim 16, wherein said setting means controls an intensity of theprocess which is performed for the black character portion by saidprocessing means.
 18. An apparatus according to claim 10, wherein saidsetting means and said display means are composed of a touch paneldisplay.